FIG. 1. Index map of a portion of southern California, showing some of the areas of crystalline limestone.         At Crestmore the limestone occurs as two irregular, very roughly parallel, lenticular bodies whose principal portions have dips up to 45° E or ENE. The prevalent N or NNW strike conforms to the trend of the Peninsular Range to the south, and is almost perpendicular to that of certain other metamorphic rocks near Riverside, suggesting that this region is one of structural transition to the E-W strikes prevalent at Cascade canyon and elsewhere in the "Transverse" ranges to the north. The lower (western) limestone body at Crestmore is overlain by a thin, discontinuous band of quartzite or quartz mica schist and there are other highly siliceous masses not far away. The lower lens is commonly called the Chino limestone. It is relatively pure. The upper (eastern) lens is sometimes, but not always, called the Sky Blue limestone. It is intruded by large bodies of quartz monzonite porphyry as well as by the enveloping quartz diorite. The porphyry is of variable composition and texture, and probably has been contaminated by the assimilation of limestone or in other ways. Numerous large and small pegmatite dikes cut the quartz monzonite porphyry and extend into the adjacent rocks, especially into the great masses of garnet-rich contact rocks which have developed from the original limestone.       The Commercial, Wet Weather and Lone Star quarries have been excavated in the Sky Blue limestone and accompanying silicate rocks. The present face on the west side of the Commercial quarry (Fig. 4) is chiefly cut in porphyry and contact rock.       The quartz monzonite porphyry clearly intrudes the limestones and contact rocks. The porphyry is probably also younger than the quartz diorite. Chino Limestone       The Chino Hill limestone of Eakle (4), called Chino quarry limestone by Daly (19), has been well described lithologically by these authors. It is typically composed of bands a few inches or a few feet thick of alternating coarse white crystalline limestone and somewhat yellowish predazzite. Graphite flakes are widely disseminated through the limestone but are far from universal. The brucite in the predazzite is pseudomorphic after octahedral periclase. The grains of brucite are commonly one to two millimeters across and are surrounded by still larger anhedrons of calcite, making a rock which is considerably coarser grained than the type predazzite, but otherwise very similar in appearance.       The Chino limestone lens dips up to 45° east, is at least 2000 feet long, and extends down the dip at least 1200 feet (to sea level). The upper and lower surfaces are both uneven. The maximum thickness has proved to be about 300 feet. Practically the whole original outcrop of the Chino limestone has now been removed by quarrying and mining operations and its site is marked by a glory hole two hundred feet deep in the center. Sky Blue Limestone       The upper or Sky Blue limestone has an arcuate outcrop, as indicated by the positions of the Lone Star and Wet Weather quarries and the 910-foot level of Commerical quarry (Fig. 3 map). The observable suggestions of bedding dip mostly E or NE (SE in Lone Star). Apparently the limestone was several hundred feet thick in Wet Weather quarry, but it thins to almost nothing between Wet Weather and the 910-foot level, the limestone beds here having been largely converted into contact rock (Fig. 2).

     

FIG. 2. Sky Blue limestone at 900 feet above sea level. Slightly modified from records of Riverside Cement Co. Map ruled at 100-foot intervals.       The structure of the limestone is uncertain. It may be a nearly isoclinal fold, with a longer E-dipping limb extending south through the 910-foot level, and a shorter SE-dipping limb marked by the shallow, high-level southwest extension of Lone Star quarry (not shown in Fig. 2).       The Sky Blue limestone has two facies, one of which is white like the Chino limestone and locally contains similar yellow predazzite beds. But close to the intrusive quartz monzonite porphyry and its pegmatites, that is, in or near the great masses of contact rock, this limestone has commonly developed a striking sky blue color. Masses of blue rock fifty feet thick are practically pure calcite. Elsewhere patches of the blue limestone, the size of a man's hand, spot the garnet and idocrase-rich contact rock.       This rock was called the Sky Blue quarry limestone by Daly (19). Quartzite and Schist       Above the Chino limestone, and usually separated from it by a quartz diorite sill, there are commonly a few feet of quartzite and quartz-biotite schist. These rocks are similar to those much more extensively developed west of Crestmore, in the Jurupa Hills. Perris Quartz Diorite       The country rock about Crestmore and Riverside and extending far to the south to the vicinity of Perris2 is a fairly uniform quartz-biotite diorite, which locally becomes a granodiorite through the presence of relatively small amounts of orthoclase. The quartz diorite often contains green hornblende in addition to the brown biotite. The Perris quartz diorite is usually gneissoid with streaks of the dark minerals and often numerous small lens-shaped dark inclusions. The gneissoid banding is roughly parallel to the elongation of the larger included masses of the metamorphosed sediments or dark colored igneous rocks. Quartz Monzonite Porphyry       Two or three large masses of quartz monzonite porphyry cut the limestones and contact rocks in the Commercial quarry. A finer grained, somewhat similar intrusive rock was also present as a pipe in the Chino limestone. The porphyry comes into contact with the Perris quartz diorite at the extreme south end of our section (Fig. 3) but here the age relationships are not entirely certain. The porphyry is probably younger than the quartz diorite, as indicated by Daly (19).       The typical quartz monzonite porphyry is a massive rock which contains about equal quantities of orthoclase and oligoclase, with abundant quartz and scattered grains and aggregates of pale pyroxene. The phenocrysts of feldspar are commonly one or two millimeters in diameter and the individual grains of pyroxene somewhat smaller. The feldspars are anhedral and the pyroxene grains are both anhedral and commonly clumped together as irregular aggregates. The ground mass is microcrystalline and made up of anhedral grains. The texture is an unusual one for an igneous rock and suggests secondary changes after its first crystallization or partial crystallization.

FIG. 3. Section across the Commercial quarry, 1940. Index map ruled at 100-foot intervals.          In the northern part of Commercial quarry and on the south wall of Wet Weather quarry, the porphyry is more varied in texture and mineral composition, and much of it is quite dark colored. Quartz is rare or absent. A sample collected thirty feet east of station 31 (Wet Weather quarry) is all oligoclase and pyroxene. One from station 9 (Commercial quarry) is mostly alkali feldspar and green hornblende. Mixed Rock       Between our locations 6 and 10 (Figs. 3 and 5) unusual types of quartz monzonite porphyry are so inextricably mixed with contact rock and pegmatite that the whole zone is mapped together as a mass of mixed rock. Part of the quartz monzonite porphyry of this area contains pale brown garnet, and much of the remainder is of the dark colored type, lacking quartz and of variable mineral composition. There is a common absence of the porphyritic texture, and locally an irregular, almost gneissoid banding. Pegmatite       Quartz Monzonite Porphyry Pegmatites. Pegmatites were found to be abundant in the Commercial quarry by Eakle (4), but very few were prominent during Daly's (19) period of study. Since the 1938 quarrying, pegmatites are again striking features of the face. They are shown rather diagrammatically in Figs. 3 and 6. They are more numerous than indicated, especially in the mixed rock. They occur commonly as clean-cut dikes in porphyry and contact rock, rarely extending as much as two or three feet into pure limestone. They are also present, more rarely, as vaguely bounded irregular areas in the porphyry, especially south of station 16.       The typical pegmatite of the Commercial quarry shows the usual variable grain size, ranging from relatively fine graphic granite up to large individual crystals of feldspar 15 or 20 centimeters across. The principal minerals, all of which are usually present, are quartz, microcline, and oligoclase or, less commonly, albite. The other constituents are fairly constant in a single dike, but vary considerably from the north to the south end of the Commercial quarry face. At the north end, pale green epidote is present, and locally also axinite, treanorite, prehnite, datolite, zoisite (var, thulite), colorless garnet, zircon and several zeolites. At the south end, the rather large vertical dike near station 16 is characterized by 10% to 40% of andradite garnet in crystals one or two centimeters across. Treanorite, with a composition close to allanite, is fairly abundant in some dikes, notably in that containing andradite.       The northern dikes are characterized by cavities into which project crystals of microcline or epidote, or zeolites. Some of the cavities are partially filled with coarse anhedral blue calcite, just like that of the Sky Blue limestone, now obviously in the process of removal by solution. In such cases the calcite may represent the remains of blue limestone inclusions, especially as many inch-long bits and rarer larger masses of blue calcite, or calcite and wollastonite, are also present in the pegmatites. However, Kelley (22) has found blue calcite veinlets which must be secondary.       Much less common than the pegmatites are veins of pegmatitec aspect, which may lack either quartz or feldspar. Quartz Diorite Pegmatites.        Pegmatites are fully as abundant in and near the quartz diorite as they are in and near the porphyry. However, most such dikes are outside the small area with which this paper is concerned. Contact Rocks       Normal quartz monzonite porphyry is almost everywhere separated from limestone by five to one hundred feet of contact rock. The most widespread type is composed primarily of grossularite garnet, with or without grass-green diopside. This rock is prominent on the summit of Sky Blue Hill and makes up a large part of the area of contact rock between stations 12 and 16 (Fig. 3). Near station 14 in the southeast part of the latter mass, and elsewhere, the garnet-rich material grades rapidly but irregularly into a rock composed in whole or in part of pale green or brown idocrase. Monticellite accompanies idocrase, and also forms almost pure brown or gray granular masses near limestone, or occurs as gray spots in the limestone. Elsewhere, and especially in the vicinity of residual calcite, very pale yellow-green diopside is present in large cleavable masses or well-formed crystals up to 5 or 10 centimeters in diameter (21). Along the south wall of Lone Star quarry a thin, nearly vertical sheet of fine grained, spurrite-bearing rock is a prominent element of the narrow contact zone which separates the porphyry, on the south, from the nearly pure limestone to the north. Locally, as in Lone Star quarry or at the extreme southern limit of our Commercial quarry section (quartz diorite contact, Fig. 3), masses of coarsely crystalline or fine silky white wollastonite are striking but minor features of the limestone side of contact rock. Numerous other mineral combinations are present and are discussed in more detail in connection with the profiles or the individual minerals.       At many places in the quartz monzonite porphyry contact rock and in the mixed rock, there are (lark gray lenses of more or less decomposed biotite schist or gneiss, rarely more than five feet thick or fifteen feet long. Below station 7 a relatively fresh example is an oligoclase-biotite-hornblende-diopside rock, with perhaps 50% oligoclase. This biotite is brown in section, the hornblende green. The mica schist is perhaps the most puzzling part of the contact rock.

     

Fig. 4. Composite photograph of Commercial quarry face, February, 1940. QMP, quartz monzonite porphyry; Ls, limestone; Con, contact rock.       COMMERCIAL QUARRY PROFILE       As shown in Fig. 4, Commercial quarry is a bench cut deeply into the east side of Sky Blue Hill. Its floor is about 935 feet above sea level. The photograph (Fig. 4) and profile (Fig. 3) show the face on the west and northwest sides of this quarry as it was in late 1939 and early 1940. These figures also show approximately the condition which prevailed from 1916 to 1938, during the period of almost complete inactivity in Commercial quarry. In the autumn of 1938 much talus material was removed and the lower part of the face was cut back 10 to 50 feet between stations 11 and 14, without making great changes in the types of rock exposed. In 1939 a trench-like cut about 25 feet deep was excavated in the floor, extending west and south about 200 feet from the east edge of the quarry, almost entirely in limestone of varying degrees of purity. We are calling this new excavation the 910-foot level of the Commercial quarry.       Our Commercial quarry profile (Fig. 3) does not show the 910-foot level, but does begin just to the north of it where banded limestone and other rocks are exposed in the slope which extends down from the edge of Commercial quarry to the deeper Wet Weather quarry. The banding, especially where due to brucite nodules in calcite, is considered to represent original bedding, even though other types of banding, especially on the 910-foot level, are in planes almost at right angles to each other and may be due to replacement along joints. The brucite banding roughly parallels the boundaries of the limestone lens, where these are known.        Fig. 5. Mixed rock beneath limestone of station 7, Commercial quarry, November, 1940. Man's hand points to one of several angular blocks of garnet rock, darker than the enveloping endomorphic monzonite porphyry. Lower right, larger mass of garnet rock, shown as such in Fig. 3. Lightest bands and veinlets mostly pegmatite. Left center, dark lens of biotite schist.       The banded limestone of stations 5 and 7 is underlain by a complex of contact rock, pegmatite and abnormal monzonite porphyry. Some details of this mixed rock are shown in Fig. 5. Others will be described in connection with a more detailed profile of the Wet Weather quarry wall. At and near the edge of the normal quartz monzonite porphyry, south of station 9, there is a somewhat similar migmatite. Numerous inclusions of garnet rock make a vaguely bounded band in the porphyry 10 to 15 feet from the contact at 9.       The following notes concern the main part of the face (AB on map and profile), and supplement the descriptions under the headings "Crestmore Rocks" and "Notes on Individual Minerals."       The pegmatite shown near station 10 is notable for its large epidote crystals projecting into cavities. Apparently this is the "coarse grained" rock mentioned by Kelley (22). The pegmatites near the top of the cliff above station 9 contained thin but extensive vugs lined with stout prismatic microcline crystals up to 15 cm. across. Microcline crystals of similar size and habit, showing Carlsbad twinning, were present in the pegmatites of the mixed rock below station 7, but there they were enclosed in clear massive quartz. The pegmatites between 7 and 9 have been the sources of specimens showing (1) thin blades of purple axinite, (2) pink thulite with oligoclase and microcline, (3) pale green datolite and green and pinkish prehnite, (4) zeolites both massive and in druses, and (5) fine clear apophyllite in cavities, - all in addition to the epidote mentioned above and a number of other minerals, as indicated elsewhere in this paper.       At the southern edge of the largest mass of garnet contact rock, near station 14, there are large masses of pale green idocrase which are called "californite" by collectors. Formerly, east of the present face, pale green pyramidal crystals of idocrase, one or two centimeters across, were thickly distributed through brownish contact rock composed chiefly of monticellite and custerite. Similar material now falls from the cliff above station 9.       Station 15 marks the bottom of a V-shaped downward extension of the summit garnet rock. The blue calcite veins in the garnet contain numerous long prisms of scapolite. Secondary radial phillipsite and a little translucent stilbite are also found here, and opalization is extensive.       The two principal surfaces of quartz monzonite porphyry which are exposed in the face, one between stations 9 and 12, the other between 16 and 18, are strikingly jointed. The most prominent joint system, approximately N 20°W 45°NE, is nearly but not exactly parallel to the contact with garnet rock above station 9 and also with the banding in the limestone at 5. Other prominent joints in the porphyry are nearly flat, perhaps with a NE dip of 0°-5°. At station 15 a prominent fault (?) running N 50°E 70°SE, extends into contact rock.       At "A", which marks the south end of the quarry face, the contact zone between limestone and quartz diorite is mostly garnet and wollastonite, and only a few feet thick, thus emphasizing the exceptional nature of the thick contact zones usually present alongside the quartz monzonite porphyry.

   

FIG. 6. South wall of Wet Weather quarry, 1940.           WET WEATHER QUARRY PROFILE       Exceptionally clear intrusive relationships, and the only example of the sharp segregation of the contact minerals into distinctive zones, are to be seen on the south wall of Wet Weather quarry, shown in Fig. 6. This section includes most of the BC portion of Fig. 3, seen in reverse. The central portion of the Wet Weather profile is shown in the photograph of the quarry, Fig. 7.       Fig. 7. South wall of Wet Weather quarry, September, 1940. Ls, limestone; Con, contact rock. Location numbers same as in Fig. 6.       At the left side of Fig. 6, the bedding in the limestone is indicated both by jointing and by brucite streaks 1 cm. thick and spaced at intervals of from 3 to 5 cms. The thickness of clearly bedded limestone is only 20 feet. The bedded limestone is underlain by a few feet of banded mixed rock. Underneath the banded rock is a complex of garnet rock cut by quartz monzonite porphyry stringers and succeeded by idocrase-diopside rock which apparently has developed down the dip of the bedded blue limestone below station 5, Commercial quarry.       Above station 29 a small mass of pure blue limestone is backed by and apparently almost surrounded by brown monticellite rock. A 4-inch layer of limestone adjacent to the monticellite is thickly studded with wollastonite and crestmoreite, cut by veinlets which may be altered thaumasite.       An idocrase-diopside zone follows the monticellite, between stations 29 and 30. This zone also contains monticellite, spurrite, and other minerals. It includes some quartz monzonite porphyry streaks, especially along its southwestern margin.       The limestone above 30 contains good crystals of idocrase and diopside, and rarely monticellite in prisms up to 8 cm. across, as well as large, 1 to 3 cm. pseudomorphs of crestmoreite after wilkeite.       Above station 30 pegmatite lenses and stringers are numerous. One lens in garnet rock is 12-18 inches thick and made up of medium to coarse grained microcline, oligoclase and andradite. It is shown very diagrammatically, partly because of dislocations due to blasting. A second lens cuts two feet into pure limestone; beyond its nose on the limestone cliff scattered crystals of green idocrase (?) seem to represent an extension of the pegmatitic influence. A nearby compound wollastonite-pegmatite veinlet between blue limestone and idocrase-diopside rock is composed of two layers. On the idocrase-diopside side there is fine-bladed wollastonite crystallized perpendicular to the walls. On the blue calcite side there are closely packed microcline crystals, without quartz, embedded in wollastonite and spotted with dark green pyroxene crystals. Some of the microcline crystals are shot through with wollastonite blades. The series of pegmatites along the limestone contact between stations 30 and 7 is one of the most persistent zones of this rock now exposed in the quarries. Many of the higher dikelets are not shown in Fig. 6.       West of location 30 the profile is simpler. Limestone remnants of the large mass excavated in the making of Wet Weather quarry remain still adhering to the silicate wall. Garnet-rich contact rock makes a layer only a very few feet thick between blue limestone and mixed rock which to the west becomes more and more predominantly a quartz monzonite porphyry. The most exceptional feature is the development of abundant black prisms of Mineral B (ludwigite?) in the vein-like margin of the limestone body at location 31.       LONE STAR QUARRY       Lone Star quarry has now (November, 1940) been excavated farther south than shown on the map of Fig. 3. There is now only a narrow ridge between Lone Star and Commercial quarries. The south wall of Lone Star presents a huge face of contact rock with blue calcite masses adhering to it in places, and quartz monzonite porphyry showing through where quarrying has removed both limestone and contact rock. The face is very steep (80°), rising over 100 feet above the Lone Star floor and at the east end continuing down to the floor of the Wet Weather Quarry 100 feet lower.       Quartz Diorite Contact Rock. At the west side of Lone Star quarry the enveloping quartz diorite is exposed, its contact with the overlying limestone lying N 52° E 45° SE. This contact also emerges 50 or 60 feet lower in the west wall of Wet Weather quarry. The limestone in contact with the quartz diorite is white with a fairly uniform development of red garnet and wollastonite contact rock about one foot thick. Epidote and quartz occur in small pegmatites projecting slightly into the calcite. Brucite is the commonest accessory mineral in the mass of the limestone, in bands roughly parallel to the quartz diorite contact. Chondrodite in dark green grains and 1 mm. crystals was found in very rare and limited occurrences near the contact; phlogopite in red-brown flakes and 5 mm. crystals rarely; magnetite as 1 mm. octahedrons in predazzite rarely; arsenopyrite, pyrite and pyrrhotite rare, near the contact; graphite rare; hydrotroilite rather abundant. The contact between the quartz monzonite porphyry and the quartz diorite cannot be seen here as yet.       Quartz Monzonite Porphyry Contact Rock. The layer of blue calcite and contact rock on the face of the quartz monzonite porphyry is here only 15 to 20 feet thick, and the change from blue to white limestone probably cuts across the banding (bedding?) of the brucite limestone, though we did not observe the progress of quarrying continuously and so cannot be entirely certain on this point. The principal contact minerals here are massive garnet, wollastonite, diopside, idocrase, monticellite and spurrite. Metamorphic zones near the quartz monzonite porphyry contact cannot be well ascertained, but the presence of large blocks of dark gray-green spurrite-bearing rock in the talus all along the face is notable. This rather fine-grained, massive rock also contains merwinite, gehlenite and monticellite, though not all are present in every sample. The largest block of spurrite rock found on the quarry floor was over four feet thick, least dimension, with veins and surfaces of silky, soft white thaumasite up to 5 cm. thick. Under the lens the thaumasite is seen to occur as closely grouped, radiating, acicular, hexagonal crystals with flat basal terminations.       Large blocks of pegmatite which have been blasted from the east end of the Lone Star face; are mostly very similar to those which have fallen into Commercial quarry from the opposite side of the same ridge. Exceptionally the pegmatitic masses contain blue calcite and wollastonite with cleavage surfaces 4 or 5 cms. across, and clear, colorless apophyllite with cleavage surfaces up to 15 mm. across.       TABLE 1. MINERALS OF CRESTAIORE AND VICINITY Minerals Occurrence Remarks Number A B C D E F G H I Legend: A:Accessory Mineral C:Common F:Frequent G: of general distribution M:Constituent mineral R:Rare G>C>F>R WW: Wet Weather quarry Ch:Chino quarry LS:Lone Start quarry Mi: from the mine 910...:910 Ft. Level. Commercial quarry 1 Actinolite 7,18             R   Felted layers on joints in contact rocks 2 Albite   M   M             3 Allanite(?) 18               R Altered; cf. treanorite 4 Andradite Garnet 16     C     F     Dark brown crystals of pegmatites 5 Andesine                   Vide Daly (19) 6 Anglesite                   Vide Eakle (4) 7 Apatite 14-16       R R         8 Apophyllite 7     R   R   R   Also silica pseudomorphs 9 Aragonite LS 910 12-14             F   Rosettes 10 Arsenopyrite Mi       R           11 Augite 15   M?     F F     Vide Daly (19) 12 Axinite 8-10     R   R R     Seams; thin purplish crystals 13 Azurite Mi, etc.       R R         14 Biotite 18 M     M M       Rock mineral 15 Bornite Mi, etc.       R R     R   16 Brucite Ch, LS, W W910       C         White or yellow grains 17 Bytownite- Anorthite     R           R Vide Daly (19) 18 Calcite G   F F M M F F F   19 Centrallasite       R           R Vide Foshag (11) 20 Cerussite 10     R       R   Alteration of galena 21 Chalcedony 9             R     22 Chalcocite     R     R     R   23 Chalcopyrite 14 WW         R       Crystals and masses in garnet calcite contact rock 24 Chondrodite WW        R           25 Chrysocolla 9             R     26 Chrysotile 15         R         27 Chlorite 29         R         28 Clinochlore LS, etc.         R         29 Clinozoisite 12     R           Pale, striated, crystals 30 Crestmoreite LS       C C       Pseudomorphs after wilkeite 31 Cuprite 14         R       Alteration of chalcopyrite 32 Custerite           R         33 Danburite                 R R M. Vonsen's collection, Petaluma, Calif. 34 Datolite 8     R             35 Deweylite                   Vide Daly (19) 36 Diallage       C             37 Diopside G   M?   R C C       38 Ellestadite WW?         R       See McConnell (24) 39 Epidote 10, etc.     C R F       Striated crystals; massive 40 Galena 10, etc.     R R F         41 Gehlenite LS, WW, 4-5, 13-14         R       With spurrite; with plazolite (?) 42 Graphite WW,Ch       C         Abundant in Chino limestone 43 Greenockite; Var.: Xanthochroite 9-10       R R R     Vide Eakle (4) 44 Grossularite Garnet G       C C C       45 Gypsum (Selenite) LS             R   With sphalerite 46 Hornblende 15 M R               47 Hematite LS, 13-15         R   R   Alteration of chalcopyrite, etc. 48 Hillebrandite; Var.: Foshagite 14-17, WW         R   R   Veins in idocrase 49 Hydromagnesite WW, Ch       F     F   Alteration of brucite 50 Hydrotroilite WW, LS       R           51 Hypersthene                   Vide Daly (19). Not at quarries 52 Idocrase G       C C C       53 Jurupaite Com             R   Vide Eakle (9) 54 Kaolinite (?) 28             R     55 Labradorite                   Rock mineral (Eakle, 4; Daly, 19) 56 Laumontite 9-11     C           Abundant in pegmatites 57 Lollingite Mi                 Vide Kelley (22) 58 Limonite WW, LS, 17             C   In contact rock, pseudomorphs after pyrite 59 Ludwigite (?) WW, LS       R          =Mineral B 60 Magnesite (?) 910             R   Dense white veinlets; indices low, some water 61 Magnetite WW, 10-11 A A   R R       1 mm. crystals in predazzite 62 Malachite 9-11             R   In garnet rock 63 Manganite (?) 14     R   R         64 Merwinite WW, 13         F       With spurrite; fine grained 65 Microcline 8-15     M             66 Molybdenite Mi           R   R From mine, with garnet rock 67 Monticellite 8-14 WW, LS, 910       C C       Usually brown or pink or glassy gray 68 Montmorillonite Mi             R   With prehnite, from the mine 69 Muscovite                 C In schist and quartzite 70 Nontronite 15, etc.             C     71 Okenite           R       Vide Eakle (4) 72 Oligoclase 8-15,  etc. M M M             73 Opal (Common) G             C          (Hyalite) G             F     74 Orthoclase G M M               75 Periclase         R         From mine, etc. 76 Phillipsite 15         R         77 Phlogopite 7-8, Ch, LS         F         78 Plazolite 14         R       Crystals; (?) massive, with gehlenite 79 Prehnite 8-9, etc.     C             80 Pyrite   A A A   R         81 Pyrrhotite WW, Ch       R C       Small crystals; large masses 82 Quartz G M M M   C         83 Realgar 14         R       In brown monticellite 84 Riversideite 14         C       Veinlets in idocrase. ?=crestmoreite 85 Rutile 15, WW         R     R   86 Scapolite 15, WW         R       White crystals in calcite veins in garnet; etc. 87 Sepiolite                 R R Vide Daly (19) 88 Sericite               R R Especially in seams 89 Serpentine 910       R R         90 Sphalerite Ch     R   R R       91 Sphene 15, etc. A A A     R       92 Spinel 13-14, 910         R       Blue grains and crystals in pale green grossularite 93 Spurrite 29,LS, 4-5, 13-14         C         94 Stibnite WW         R         95 Stilbite 15     R   R       With scapolite and phillipsite in calcite veins in garnet 96 Strontianite LS                   97 Talc?  WW         R       With brown tourmaline 98 Tetrahedrite                   Vide Eakle (4) 99 Thaumasite LS, WW, 910,16             C   Veins and joints in spurrite rock 100 Tilleyite           R       Vide Larsen and Dunham (16) 101 Tourmaline,       Brown WW         R         102 Tourmaline; Var.:  Schorl 10-18     R           More abundant in quartz diorite pegmatites 103 Treanorite 6-9,17     C           Similar to allanite; fresh, glass?  crystals 104 Uralite                   Vide Daly (19) 105 Vermiculite LS R           R   In quartz diorite pegmatites 106 Wilkeite  910, 8,  14, 29       F R       Also from SE wall of Lone Star quarry 107 Wollastonite G     F F C       Fine crystals; silky masses 108 Xanthophyllite 910, 13-16, WW       F F       Usually in idocrase or calcite 109 Zircon  8-15 A A R           Dark brown crystals up to 5 mm. long 110 Zoisite; Var.: Thulite 8-10     R           Pink crystals up to 15 mm. long Mineral B WW, LS       R         Fine crystals up to 15 mm. long  Ludwigite (?) Mineral C  LS             R   White, radiating, on altered wollastonite Mineral D LS             R   White, radiating CaMg silicate in peg.- like vein cutting idocrase Mineral F 14, etc.             F   Blue films of CuCaAlSi - carbonate on joint cracks in garnet rock Mineral G  910         R       Brown pseudomorphs; Mg. silicate Mineral H 8-17     R           A high-index titanium-bearing tourmaline Mineral J 910         R       A white, silky radial CaAl silicate with Mineral G  Mineral K 910             F   White, chalky prisms of CaAl Si- CO3 on Mineral P Mineral L 15     R           White, soft TbCa silicate in andradite-feldspar-treanorite peg. Mineral M 15     R           An isotropic substance with Mineral L Mineral N LS             C   Thin yellow films of PbCu Ca vanadate on joint surfaces Mineral O 910             R   2-5 mm. yellow crystals resembling clinohumite, in blue cal cite Mineral P 910             R   Colorless, triclinic crystals seams in spurrite-calcite rock Mineral Q W W             R   Soft white fibers on loose limestone blocks  Occurrences   A. Station ( in Comm. and Wet Weather quarries)   B. Quartz Diorite   C. Quartz Monzonite Porphyry   D. Quartz Monzonite Porphyry Pegmatite   E.  Limestone, including Predazzite   F.  Contact Rocks   G.  Mixed Rock   H.  Secondary Veins; Weathering Products    I.  Miscellaneous and Uncertain         NOTES ON INDIVIDUAL MINERALS       ACTINOLITE. Found somewhat sparingly near stations 7 and 18. At the former locality, the mineral occurs as coarsely fibrous, silky masses of pure actinolite, up to 8 cm. in length and 5 mm. in thickness. Chlorite green in color, it occurs in a coarse quartz-calcite-epidote vein of pegmatitic aspect. At the latter locality, actinolite in blade-like crystals averaging 5 X 30 mm. in size is found as a minor constituent of an altered pegmatite which cuts the quartz diorite and probably is genetically related to that rock.       ANDRADITE GARNET. Occurs abundantly near station 16 in a pegmatite composed of quartz, microcline, oligoclase, treanorite and chloritized pyroxene. The simple dodecahedral crystals found here measure up to 2 cm. in diameter, are semi-transparent, and hair brown in color. Spectrographic examination indicates a Ca Fe silicate, with Al subordinate to Fe, and Mg less than 1%. The refractive index, far above 1.74, and the specific gravity, 3.67 or a little higher, suggest an andradite containing 30%-40% of the grossularite molecule.       APATITE: Rare, between stations 14 and 16, as pale green, clouded, prismatic crystals 2-5 cm. in length, with rounded terminations. Mineral associates are coarsely crystalline blue calcite, idocrase, grossularite and diopside. Minute blue apatite crystals of the type mentioned by Eakle (4) now can be found only on the old Commercial quarry dump.       APOPHYLLITE. Fine, clear, fresh, short pyramidal crystals. Especially from Lone Star quarry, in cavities in limestone (or calcite pegmatite). Also, in Lone Star quarry and on the Commercial 910-foot level, completely altered to silica pseudomorphs which preserve the birefringence and interference figure of apophyllite. These pseudomorphs have been studied by E. H. Bailey.       ARAGONITE,. Of rather general occurrence in crusts and veinlets, but found notably in two localities: (1) in the Lone Star quarry, as acicular crystals in gleaming stellate groups up to 15 mm, in diameter, lining small veinlets or cavities in limestone, (2) on the 910-foot level of the Commercial quarry, as similar rosettes of transparent crystals averaging 1 X 7 mm. in size, and showing b, k and m faces. Occurrences of the crust-like type of aragonite have been noted especially near stations 12 and 14 of the Commercial quarry.       BRUCITE. As alteration pseudomorphs of periclase, locally abundant in the limestone of Lone Star and Wet Weather quarries and the 910-foot level of Commercial quarry. Waxy, gray grains, 1-5 mm. in diameter. Much rarer here than in the Chino limestone.       CHLORITE. Found as thin, blue-green 1 X 1 mm. plates in blue calcite above station 29, Wet Weather quarry, with grossularite and wilkeite in blue limestone. Also very pale green clinochlore or prochlorite in Lone Star quarry, as groups of 5-10 mm. flakes forming the matrix of pale diopside crystals; biaxial, +, 2V 5°-10°, β=α=1.582 ±.002, γ-α=.010±.       The most striking and exceptional chlorite is colorless and transparent, like isinglass, occurring sparingly as flexible plates 6 to 8 cm. across, associated with monticellite-idocrase rock near station 16. A slightly ferruginous Mg Al silicate; +, 2V practically 0°, α=β= 1.577±.002, γ=1.582±.003.       CLINOZOISITE. Found sparingly near station 12, in well-developed, pale brownish-green crystals, slightly striated parallel to elongation (b), and measuring up to 15 mm. in length. The crystals occurred as divergent groups in a feldspathic pegmatite cutting garnet rock. This clinozoisite is practically neutral with strong dispersion of the optic axes, and shows anomalous blue and yellow interference colors. Indices vary slightly about the following values: α=1.713, β=1.718, γ=1.723.       CRESTMOREITE. The soft, white, silky, hydrous calcium silicate minerals at Crestmore are not easily distinguished. Their optical properties are variable. Perhaps all should be called crestmoreite; perhaps riversideite (Eakle, 4) and even a third mineral should be recognized.       CUPRITE (ferruginous): Found sparingly near station 14, both massive and as pseudomorphs of chalcopyrite measuring up to 1 X 2 cm. in size, in a garnet-calcite contact zone. Identification somewhat doubtful.       DIOPSIDE. See pyroxene.       DOLOMITE. Searched for, but not found at Crestmore.       FORSTERITE. Searched for, but not yet found at Crestmore, though it is present at Victoria quarry a few miles away.       GEHLENITE. Rarely found near station 13, as grayish white to black, granular Streaks, interleaved with plazolite (f) in braided veinlets averaging about 1 mm. in thickness; ω-1.659±.002, some grains anomalously biaxial with 2V about 5°. Also, in the Wet Weather quarry, below station 5, in spurrite-merwinite rock as colorless or pale yellow, smooth, 1/2 - 1 mm. glassy grains in bluish limestone (Cf. Larsen & Foshag, ref. 10). It also occurs with euhedral idocrase and custerite (Tilley, ref. 14).       GROSSULARITE GARNET. This common brown garnet is the most abundant contact mineral at Crestmore, as has been emphasized in previous papers. It frequently occurs in pure masses, some of which, when finely crystalline, have a sugary appearance, but when coarser, against calcite, may also show dodecahedral crystals up to several centimeters in diameter. Trapezohedral (hll) faces are rarer; they appear, for example, on a very pale green type, found with the yellow-brown form and with blue ceylonite near stations 13 and 14. Palest yellow, minute glassy garnets from a prehnite pegmatite near station 7 show dodecahedral and tetrahexahedral faces; they are slightly birefringent, with polysynthetic twinning and n=1.76±.        The various grossularites have not been specially studied, but indices have been determined ranging from 1.745 ±.003 to 1.780 ±.010.       The dark red-brown garnets associated with the dark green diopside in the quartz diorite contact zone on the west side of the Lone Star quarry appear from spectrographic data to be manganiferous grossularite-andradites. They develop many faced crystals against limestone, with large dodecahedral faces bordered by narrow hexoctahedral and trapezohedral faces. The paler grossularites in the quartz monzonite porphyry contact zone, a hundred feet southeast in the same quarry, are simple dodecahedrons.       HILLEBRANDITE, var. FOSHAGITE. Chalky white, fibrous, relatively brittle. Found as (1) irregular masses up to 1 cm. or more across, in idocrase rock near station 14; (2) near station 17 in veins 1 cm. thick and 10 cm. or more in length, intimately mingled with finely divided calcite in minor fault cracks, and closely resembling fine grained amphibole asbestos; (3) the original type material of Eakle (ref. l2), which has again been found in the Wet Weather quarry as cross-fiber masses 8-10 cm. in length, cutting greenish idocrase-rich rock. Some of the second type is so fine-grained that the indices of refraction and birefringence are intermediate between those of calcite and foshagite.       LAUMONTITE. Probably the commonest zeolite at Crestmore. Found in pegmatite dikes and pegmatite-like calcite-bearing masses, such as occur near stations 9 and 11, where it is seen as white, friable masses (variety caporcianite), or interlacing crystals varying greatly in size. Also in more compact masses of radiating or parallel columnar units 3 to 8 mm. in length, and as 5 mm. crystals in cavities, showing the forms {110} and {001}. Optically variable; γ ranges from 1.515 to 1.526. In one case great dispersion r>v. The caporcianite variety has γ=1.515-1.517 and extinction of 40°-42° on cleavage pieces.       MONTICELLITE. Monticellite was reported "of limited development and soon exhausted" by Eakle in 1917; and Daly listed it as rare in 1935. One type was described in detail by Moehlman and Gonyer (18). Our investigations have revealed monticellite in a wide range of color, abundantly present, in all the quarries except the Chino limestone quarries on the west side of Sky Blue Hill. It is commonly associated with blue calcite and with all the contact rocks owing their origin to the quartz monzonite porphyry intrusion, except wollastonite and garnet rocks. Even with these latter minerals, direct association has been observed by Moehlman and Gonyer (18). Monticellite occurs most abundantly between idocrase-diopside rock and blue calcite, frequently extending into each.       The commonest variety is massive and granular, usually pale to dark brown in color, more rarely practically colorless. The largest mass is present in Wet Weather quarry near station 29 (Fig. 6). Also at station 14, Commercial quarry; and at station 13 - pale gray, with pink wilkeite and white crestmoreite. Blocks from the ridge northwest of station 8 show this variety, with custerite, forming the matrix of pale idocrase crystals (cf. Tilley, 1928). In Lone Star quarry it occurred in large quantity as nodular masses from 2 inches to 18 inches in diameter, which look like boulders or concretions. None were found in matrix. Some of these nodules, when broken, are found to contain inclusions of green idocrase; others change from brown to gray and colorless monticellite within, and contain blue calcite with crestmoreite in the center. The crestmoreite is often seen in the monticellite also.       The brown variety of monticellite occasionally forms prismatic crystals extending into the blue calcite, fine ones having been found at the Wet Weather and Commercial locations mentioned above. One 15 X 17 mm. crystal from station 14 shows {110} and {111} forms.       At station 14, Commercial quarry, pale yellowish and colorless monticellite occurs with spurrite and gehlenite. Also a rarer distinctly yellow form fills spaces in idocrase, associated with foshagite.       On the new 910-foot level of Commercial quarry, gray, vitreous, 10 to 20 mm. grains and crystals of monticellite occur in bands in the spurrite-calcite rock near yellow wilkeite. The brown variety also occurred here with blue calcite and green xanthophyllite crystals.       Monticellite (the Mineral "A" of Larsen and Foshag, ref. 10) is also a constituent, with merwinite, etc., of the rather fine-grained gray-green spurrite rock, which is so abundant along the southeast margin of the limestone in Lone Star quarry. Great blocks of this rock have fallen into Wet Weather quarry, and it may also have occurred in place there.       Optically the various color varieties of monticellite are similar, with β=1.645-1.653, γ-α=.014±.003, sign negative with 2V=80°-85°. G=3.06-3.11. The mineral is soluble in hot concentrated HCl, and yields appreciable amounts of Fe and Al, in addition to the predominant Ca, Mg, and Si.       MONTMORILLONITE. Soft, white and waxy clay-like material associated with calcite and granular prehnite in a four-inch vein along a N 30° E drift on the 700-foot level of the mine beneath the Chino quarry.       OPAL. (1) Colorless hyalite, more abundant than was indicated by Eakle (4). Commonly found as a coating on joint-planes, especially in garnet rock near station 12. (2) Brownish to black, banded "wood-opal", found in quantity near station 18, as the replacement of travertine, altered garnet, monticellite and fault-gouge materials.       PHILLIPSITE. Found very rarely on joint surfaces as lustrous silky-white, spherical or divergent, radiate groups of crystals 15-20 mm. in length: (1) near station 15 on contact rock composed of scapolite, blue calcite and cinnamon garnet, (2) on blue limestone of the 910-foot level. γ-α=.005; indices close to 1.500. Fibers show Z^c 6°-10°. H=4.5; G=2.16; F=2. Hydrous Al silicate, gelatinizing with HCl.       PHLOGOPITE. Occurs in relatively large flakes in limestone near station 30 and at station 29, both in Wet Weather quarry; also in the south end of the Chino quarry, and in the mine. At the first locality, greenish to reddish brown plates several centimeters across were found in a single specimen of white limestone; at 29, more numerous smaller green plates; at the third locality, small brown crystals 1 mm. or less in diameter, in limestone close to a contact with lavender, pyrrhotite-rich quartzite. From the Chino limestone of the mine, specimens of phlogopite measuring up to 4 cm. in diameter have been obtained.       In addition to the above localities, phlogopite has recently been found in the limestone of Lone Star and Wet Weather quarries, as colorless or pale green microscopic grains associated with idocrase and "Mineral B." 2V=0°; β=γ=1.583±.002.       PLAZOLITE (?). At station 14, white, fine-grained masses of a hydrous Ca Al silicate, containing some Mg and Fe, alternating in a braided structure with gehlenite. Somewhat opal-like in luster. Isotropic, n=1.675±.005. This material may or may not be the same substance as the minute, colorless or light yellow dodecahedral crystals described by Foshag (8). Probably the small amount of CO2 shown by Foshag's analysis is not essential. In a letter dated August 2, 1940, Foshag states that the CO2 may have come from included calcite. Pabst (23) ignored CO2 in determining the crystal structure.       PREHNITE. Found rather abundantly near stations 8 and 9 in semi-transparent green to white or brown crystalline masses, and in distinct, colorless 1 X 3 mm. crystals showing prominent {001}, {110}, and {101} faces; also common in crystalline aggregates which exhibit the usual "corrugated" surfaces. β=1.627±.003. In pegmatite, with oligoclase, quartz, datolite and treanorite.       PYROXENES. Diopside is the principal pyroxene found in the contact rocks. The very pale variety described by Merriam and Laudermilk (21) and Eakle (4), with α=1.666 and γ=1.695, has recently been found abundantly in Lone Star quarry. Good crystals up to 7 cm. long project into blue calcite. A grass green variety, +, 2V=55°-60°, α=1.670±.003, γ=1.703±.003, occurred in calcite east of the present face in Commercial quarry. The green pyroxene in the garnet rock usually has higher indices, e.g., α=1.688±.003 for a specimen from the top of Sky Blue Hill above station 9.       PYRRHOTITE. Fairly common in the Wet Weather quarry, in the Chino quarry and mine workings. In western Wet Weather quarry disseminated through limestone; also present above station 29 as lenticular masses 1 cm. or more across in a monticellite-idocrase rock. At the Chino quarry, it is found widespread granular or as crystals, especially distributed in small amounts throughout the quartzite. From the mine beneath, pyrrhotite masses weighing more than 500 pounds have been obtained occasionally, sometimes associated with "black-jack" sphalerite.       RIVERSIDEITE. See crestmoreite discussion.       SCAPOLITE. Good crystals of translucent to cloudy white scapolite, measuring 1 by 4 cm. and showing well-developed {110}, {100}, and ( l l1} faces, occur near station 15, with blue calcite in garnet rock. ω=1.566±.001 perhaps indicates dipyre. Also massive, in contact rock at station 13; ω variable, 1.553-1.576; H=5.5. Fine-grained scapolite has been found with brown tourmaline in a Wet Weather block of fine grained contact rock; its indices, ω=1.582±.002, ε approximately 1.550, indicate mizzonite. Scapolite (dipyre?) was probably abundant locally in mixed rock and pegmatite, but is hard to identify because of alteration.       SPHENE. Golden yellow, millimeter crystals of sphene are very abundant in some pegmatites. Larger brown crystals are also fairly common. A cavity in garnet rock, lined with brown sphene crystals, has been found in the southeast face of the Lone Star quarry by Mr. R. E. Campbell of Bloomington. The crystals are 5-10 mm. across, and show the common flat double wedge habit. Coarse, massive gray calcite has been partially dissolved from the cavity and much coarse massive albite remains. This sphene may be hydrothermal.       SPINEL. The dark blue-green variety of spinel known as "ceylonite" has been found near station 14, where it occurs as translucent grains 1-4 mm. in length, with pale green grossularite garnet and granular calcite. The wilkeite-bearing limestone of the 910-foot level is locally peppered with smaller, very dark green, nearly black, spinel octahedrons.       SPURRITIE. (1) Pale bluish gray and snowy, to deep sky blue and clear. Rather abundant, in masses 1 to 10 cm. across. With calcite, idocrase, etc., above station 29 (Wet Weather quarry), on the 910-foot level of Commercial quarry, with gehlenite near stations 13 and 14 in Commercial quarry, and in blocks from the top of the ridge above station 8. (2) In compact, pale to dark green, granular masses of widely varying sizes, near station 29. (3) Perhaps the most abundant constituent of the greenish gray spurrite-gehlenite-merwinite rock which makes up a considerable part of the contact rock above the southeast corner of the Lone Star quarry.       STILBITE. Very rare. In the pegmatite near station 15, in transparent, platy crystals up to 1 cm. in length, with the familiar divergent structure and characteristic, pearly luster. α=1.493±.002, γ=1.504±.003.       STRONTIANITE. Found in Lone Star quarry as white, tufted fibers in minute balls on a joint surface.       TALC?. Talc is doubtfully present as a minor constituent of a rock with brown tourmaline in Wet Weather quarry. Colorless flakes with hardness about 2; 2V=26°±4°; α=1.548 ±.005, β=1.587±.002, γ=1.589±.002.       THAUMASITE. Abundant in Lone Star quarry and elsewhere in veinlets cutting spurrite rock as described by Foshag (7) and Larsen and Foshag (10). Also with calcite and crestmoreite forming the white silky matrix of some idocrase crystals from the Wet Weather quarry.       TOURMALINE. Schorl has been found rather rarely in trigonal prisms up to 10 cm. in length in the quartz monzonite porphyry pegmatites, and thin, platy crystals 3 or 4 cm. long in seams. It is more abundant in the pegmatites associated with the quartz diorite.       Brown tourmaline prisms spotted a block of gray scapolite-bearing contact rock in Wet Weather quarry; ω= chocolate brown, 1.650±.002; ε= pale greenish tan, 1.625±.005.        VERMICULITE. Near station 18, brown to black plates up to 15 mm. in diameter, probably derived by hydration from biotite. The mineral associations are pegmatitic in character, with schorl prominent.       WILKEITE. On the basis of information furnished by Mr. R. M. Wilke of Palo Alto, under date of November 29, 1940, we conclude that the original find of wilkeite, in blue calcite with idocrase, was made in the north central part of Commercial quarry, slightly north of east of the summit of Sky Blue Hill, near 1650N 2700E, Riverside Cement Co. coordinates. The mineral is now very rare in the main Commercial quarry. A few rose-colored grains with crestmoreite rims were found with monticellite at station 13. It still occurs in limited amount in the Wet Weather quarry above station 29, in typical pale rose-colored grains up to 3 mm. across, associated with crestmoreite. Uniaxial, neg., ω=1.651 ±.001; ω-ε approx. .009 at station 13, .005 at station 29. In November, 1940, pink hexagonal crystals 5-10 mm. wide were found alongside giant wollastonite crystals in blue calcite, a few centimeters from idocrase contact rock, in great blocks which fell into Wet Weather quarry from the ridge southwest of Lone Star quarry. These crystals are uniaxial, negative, with ω=1.657+.001, ε=1.648±.002, and may be ellestadite (24). Still more recently numerous patches and veinlets of similar pink wilkeite have been found in Wet Weather blocks which fell from the steep wall just northwest of station 8 (Fig. 6).       A yellow variety (wilkeite?) occurs as numerous distorted crystals and wheat-shaped grains on the 910-foot level of the Commercial quarry, where it is associated with calcite, glassy gray monticellite, crestmoreite, idocrase, etc. The yellow variety is biaxial, with 2V commonly 38°±2°, as estimated from interference figures. It is tentatively called wilkeite rather than a related mineral, as it is a calcium phosphate-carbonate-silicate-sulphate, with low birefringence and γ= 1.647 to 1.650.       WOLLASTONITE. In addition to the numerous occurrences of the massive mineral (see under "Contact Rock" and the descriptions of the sections) well-formed crystals have recently been found at two localities. Near station 14, 1 X 2 cm. crystals show the forms {001}, {101} and (100}, the associated minerals being blue calcite and grossularite. Blocks with yard-broad surfaces covered by even better crystals have tumbled down from the ridge southeast of Lone Star quarry. These crystals have not been studied, but they apparently belong to Eakle's second type (4, p. 334).       XANTHOPHYLLITE. Colorless xanthophyllite occurs as one to three mm. flakes closely associated with the commoner green variety, at and near station 13.       ZOISITE, var. THULITE. Bright pink crystals in pegmatites high on the face above stations 8 and 10. Practically colorless under the microscope. Apparently pigmented by a little iron and still less manganese. Indices low: e.g. α=1.688±.003, γ=1.698±.003. Positive; 2V variable, ranging upward from about 60°. Intergrowths with and perhaps gradations to gray clinozoisite; the intergrowths in microscopic bands which resemble polysynthetic twin laminae.       ZIRCON. 1-3 mm. gray to brown zircon crystals, associated with oligoclase and other minerals of the pegmatites, near stations 8, 9, and 15 (cf. Foshag, ref. 8).       NEW OR UNDETERMINED MINERALS       We have twenty-five or thirty minerals from Crestmore which we have not been able to identify definitely with previously described species. Those which are briefly described below are, with two or three exceptions, thought to be new varieties or even new minerals. Those lettered B, K, L and P are considered especially worthy of further study. Several of the undetermined species which are not mentioned further in this paper, are probably zeolites.       TREANORITE. The pegmatites of the Commercial quarry contain fairly numerous black or gray, fresh, vitreous tabular crystals, usually of orthorhombic but sometimes of monoclinic aspect. The chemical composition is variable, in some cases very close to that of allanite. The optical properties are unusual for allanite or other members of the epidote group, and the interfacial angles and unit cell3 have not been reconciled with those of allanite or epidote. The name treanorite has been proposed for the crystals of this type which were first studied (27). This variable mineral is being investigated further.       MINERAL B. Slender, black orthorhombic prisms up to 20 mm. in length have been found in the Sky Blue limestone (e.g. at station 31, Wet Weather quarry) as well as at Victoria City quarry in Riverside. Chemical analysis of a very small sample by J. D. Laudermilk shows that this mineral is an aluminous iron-magnesium borate which may be closely related to ludwigite. It is strongly pleochroic: X=pale green, Y=slightly darker green, Z=dark brown. α=1.791, probably ±.002; γ-α=.095±.010. Crystallographically it has prism angles which could be reconciled with those of ludwigite and in addition numerous sharp terminal forms never before reported on ludwigite. This mineral is being investigated further by Mr. Edgar H. Bailey.       MINERAL C. Small white radiating groups of fibers locally developed in an inch-thick sheet of calcite and wollastonite in Lone Star quarry contact rock. A hydrous calcium aluminum silicate with α=1.545±.002, and γ=1.549±.002. The fibers show parallel extinction and positive elongation. This appears to be a new mineral and it may be possible to obtain sufficient material for chemical analysis and a more exact determination of the optical and other properties.       MINERAL D. A second white mineral occurring in radiated groups 5-10 mm. across, with wollastonite, in a pegmatitic vein in Lone Star quarry, is a hydrous calcium magnesium silicate with minor aluminum. Parallel extinction; + elongation. For the fresh material, α=1.513 and γ=1.532. After a summer in the laboratory: α=1.518±.002, γ=1.536±.002. As no zeolite has this composition or these properties, the mineral is considered new.       MINERAL F. A secondary mineral, occurring as definitely crystalline blue films coating joint planes of the quartz monzonite prophyry and contact rock near the southern end of Commercial quarry. It is a copper calcium aluminum silico-carbonate with low birefringence and indices close to 1.70. This mineral is rather certainly new but occurs in such small quantities that it may not be possible to obtain sufficient material for a chemical analysis.       MINERAL G. The yellow wilkeite and white crestmoreite now exposed on the 910-foot level of the Commercial quarry are in some places accompanied by centimeter-long brownish black pseudomorphs of a monoclinic mineral. Apparently identical pseudomorphs have also been found in Lone Star quarry. The principal mineral present appears to be a hydrous magnesium aluminum silicate containing some calcium and iron. Optical properties are similar to those of an impure, iron-stained clay mineral, with low birefringence and indices mostly between 1.535 and 1.545. In one case monticellite cores are present but the original monoclinic mineral is more likely to have been a diopside or chondrodite. The angles measured on one or two well-preserved pseudomorphs are fairly close to those published for chondrodite but do not fit diopside. Murdoch and Webb (25, p. 350) have reported somewhat similar pseudomorphs, with forms suggesting diopside.       MINERAL H (Titanium-rich tourmaline). Large, well-formed, black crystals in the pegmatites of Commercial quarry and also in the pegmatites at North Hill and Victoria City quarries in Riverside. Spectrographic analysis indicates a titanium-rich tourmaline. Indices high, well above 1.74.       MINERAL J. A white silky radial mineral associated with mineral G on the 910-foot level of Commercial quarry. α=1.551, γ=1.553; extinction parallel, elongation postive. hydrous calcium silicate with some aluminum present. Perhaps okenite.       MINERAL K. Associated with mineral P on joint surfaces of the contact rock on the 910-foot level, Commercial quarry. Glassy, stout, hexagonal prisms with good terminations, and good prismatic cleavages. Angle of 47° 23'±30' between basal pinacoid and hexagonal pyramid. Uniaxial, negative, ω= 1.494 ±.002, ε= 1.467 ±.003. Calcium aluminum silicocarbonate. Alters, after a few hours' or days' exposure, to snowy white pseudomorphs with lower indices and less double refraction, α finally becoming about 1.459 and γ 1.466. The change may be due to dehydration, as the product seems to be still a silico-carbonate.       MINERAL L. Minute, chalky, white, tetragonal crystals, showing pyramids and basal pinacoids, occurring in the andradite-treanorite pegmatites at the south end of the Commercial quarry. Altered to a fine-grained crystalline aggregate with indices slightly below 1.64. Impure calcium thorium silicate. Perhaps close to thorite, perhaps a new mineral.       MINERAL M. Isotropic yellow particles included in mineral L. Index 1.520±.002.        MINERAL N. Yellow-green films on joint planes of the rocks in Lone Star quarry and elsewhere, which prove to be lead copper calcium vanadate. The indices of refraction and the double refraction are both extremely high. This is either a new mineral or perhaps a mixture of known vanadates.       MINERAL O. Yellow equidimensional crystals 3 to 10 mm. across, spotting the white limestone of the 910-foot level of the Commercial quarry. Clear, glassy, and exceptionally pure. A Mg(Ca) fluosilicate. Biaxial, positive, α=1.625; β=1.636, and γ=1.655. Slightly soluble in HCl. This mineral may be a member of the humite group.       MINERAL P. A colorless CaAl Mg fluosilicate occurring as crusts and crystals in cracks of the limestone of the 910-foot level of the Commercial quarry, associated with mineral K.       MINERAL P occurs massive and also as druses of numerous small triclinic crystals with many smooth faces. The axial elements are not close to those of any triclinic mineral with similar composition. Biaxial, +, 2V 35°-40°. α=1.613±.003, β=1.619±.002, γ=1.630± .002. One excellent cleavage nearly normal to optic axial plane. This mineral is being investigated further by Mr. Edgar H. Bailey.       MINERAL Q. Soft, white, silky fibers, in cavities in limestone blocks found in Wet Weather quarry. A calcium silicate. Isotropic, n=1.482.       CRYSTALS OF CONTACT MINERALS       In the contact zone good crystal faces against calcite are shown by several minerals, especially wollastonite, diopside, idocrase, garnet, and mineral B. Diopside, phlogopite, idocrase, mineral B and Eakle's second type of wollastonite (4) are present as more or less perfect crystals isolated in calcite near silicate contact zones. More commonly diopside and garnet crystals project into calcite from masses of contact rock. Garnets are rarely, if ever, complete crystals. Idocrase also has formed perfect pyramidal crystals in a silicate matrix of monticellite and custerite. Perhaps the greatest range in crystal size is shown by idocrase pyramids, which are very abundant in the millimeter size and rarely reach diameters of 100 or even 200 millimeters.       Some details concerning crystal forms have been given in the notes on individual minerals.       ORDER OF CRYSTALLIZATION       The relative ages of the minerals in the contact zones and other rocks have been given special consideration by Dunham (17) and Daly (19). Several genetic sequences have been traced, on various types of evidence.       Pseudomorphs of brucite after periclase and crestmoreite after wilkeite are well known at Crestmore, and the products of the alteration are abundant. There are also several other cases, including laumontite after feldspar, and even garnet after idocrase. The pyramidal garnet pseudomorphs, from station 15, Commercial quarry, have the refractive index 1.747 ±.005, which suggests almost pure grossularite.       No doubt most or all of the minerals of the sharply bounded pegmatites crystallized after those of the limestone contact zones which they penetrate. The order of crystallization in the pegmatites seems obscure, except for the single case of laumontite after feldspar.       Perhaps the most striking vein mineral is the white thaumasite which occurs in seams and thicker sheets cutting spurrite-merwinite rock. Foshagite is usually in cross-fiber veins in idocrase-rich rock. Other vein minerals include aragonite and strontianite, - both perhaps quite recent crystallizations. Minerals C, D, K, P and Q are also vein minerals, cutting contact rock.       The carbonate and sulphate ore minerals listed in Table 1 are commonly associated with sulphides and are obviously oxidation products. Nontronite, vermiculite, montmorillonite, kaolinite (?) and opal are alteration products, in part at least due to weathering. Weathering has also produced manganese stains, not represented in Table 1 because their mineral identity was not determined. Minerals F and N are probably products of weathering.       CONCLUSIONS AS TO ORIGIN       All students of contact metamorphic rocks are indebted to N. L. Bowen for his illuminating discussion of contact metamorphism in siliceous limestone and dolomite.4 We take his paper as the starting point for the few suggestions we wish to make concerning the origin of the contact minerals at Crestmore. Bowen emphasizes the early disappearance of dolomite in contact metamorphism and lists the disappearance of the ten following minerals as characteristic of the stages in the metamorphism of a somewhat siliceous dolomite:       1. Tremolite 6. Monticellite       2. Forsterite  7. Akermanite       3. Diopside       8. Spurrite       4. Periclase    9. Merwinite       5. Wollastonite 10. Larnite       There have been found at Crestmore the minerals listed from 3 to 9 inclusive. But though some of the minerals are present in abundance, zones characterized by them individually (or by their absence) are missing, except very locally. Such a local series of mineral zones has been shown in Fig. 6, but its significance is not obvious, because the silicate zones lie between limestone bodies. Southeast of Lone Star quarry monticellite, - merwinite, spurrite, and gehlenite (not akermanite) are intimately intergrown in the same rock; apparently they formed contemporaneously. Finally, the calcite common in most of the contact zones contains none of the brucite after periclase which is so abundant in the limestone outside the contact zones.       The space relationships seem to indicate rather clearly a general metamorphism of the whole mass of the limestone to beds of pure crystalline limestone and beds of predazzite. Near plutonic contacts there is also the development of a garnet zone which can hardly be explained except on the assumption of the addition of silica and other elements from the magma. Locally in the vicinity of the quartz monzonite porphyry and its associated pegmatites, the garnet zone is very greatly enlarged, and is characterized by paler garnet than elsewhere, and by the presence of numerous additional silicate minerals.       The Bowen series is indirectly useful here. The presence of diopside, wollastonite, monticellite, gehlenite, spurrite, and merwinite, more or less closely associated in the additive zone, suggests the presence of circulating solutions and perhaps much lower temperatures than those minerals would indicate in dry thermal metamorphism. On the other hand, the Bowen series cannot be used for the silica-free limestone outside the contact zone, and the presence of brucite after periclase, without other members of the series, does not necessarily mean that the temperature represented by tremolite, forsterite, and diopside had been exceeded.       The real nature and mode of intrusion of the quartz monzonite porphyry are not clear to us. Its principal masses, beneath the center of Sky Blue Hill, are crowned with and irregularly penetrate garnet rock and other contact rocks, and were nearly surrounded by a collar of Sky Blue limestone, now mostly removed. No considerable faulting has been demonstrated. If the porphyry invaded a rigid block composed of limestone and fully consolidated quartz diorite, the relationships would perhaps be explained most easily on the basis of assimilation and replacement of part of the Sky Blue (and Chino) limestone. Possibly the porphyry and the associated pegmatites have merely taken the place of dissolved limestone, part of the substance of which has gone off as carbon dioxide. We have as yet ascertained neither the dimensions of the porphyry underground nor the variations in its chemical composition, and so are unable to test such a speculation quantitatively.       ACKNOWLEDGMENTS       We are indebted to the Riverside Cement Company for our base map and many courtesies. We feel especially grateful to Garner A. Beckett, president of the company, Howard R. Starke, superintendent, and R. H. Wightman, engineer. Mr. Wightman opened his records to us, and has criticized the manuscript.       Mr. Edgar H. Bailey worked with us through the academic year 1939-1940, in field and laboratory. Though he did not participate in the preparation of the manuscript, he has criticized it, and is practically a joint author. All goniometric work was done by him, and also a small part of the optical determinations here reported.       We are indebted to several members of the Claremont Colleges research staff. Dr. T. G. Kennard made numerous spectrographic determinations. Mr. David Howell contributed the laboratory photography. Mr. J. D. Laudermilk made several chemical analyses, the results of which have been used, though the analyses themselves remain unpublished.       Much of the best material which we have used was collected by Mrs. R. A. Crippen. We have also been aided by the field observations and collections of R. E. Campbell of Bloomington, Dr. J. W. Eggleston of Riverside Junior College, Howard Small of Riverside, and Melvin Swinney and Richard Strehle of Pomona College.       NOTE: Because of Dr. A. O. Woodford's recent illness he was unable to read the proof of this article. The junior authors, together with Mr. Edgar H. Bailey, assume full responsibility for any typographical errors which may be present.       BIBLIOGRAPHY OF CRESTMORE PAPERS       1. EAKLE, A. S., AND ROGERS, A. F., Wilkeite, a new mineral of the apatite group and okenite, its alteration product: Am. Jour. Sci., 37, 262-267 (1914).       2. EAKLE, A. S., Some contact metamorphic minerals in crystalline limestone at Crestmore: (Abstract) Geol. Soc. Am. Bull., 25, 125 (1914).       3. EAKLE, A. S., Xanthophyllite in crystalline limestone: Jour. Wash. Acad. Sci., 6, 332-335 (1916).       4. EAKLE, A. S., Minerals associated with crystalline limestone at Crestmore, Riverside County, California: Univ. Calif. Bull. Dept. Geol., 10, 327-360 (1917).       5. ROGERS, A. F., An American occurrence of periclase and its bearing on the origin and history of calcite-brucite rocks: Am. Jour. Sci., 46, 581-586 (1918).       6. EAKLE, A. S., New and rare minerals formed in limestone by contact metamorphism: (Abstract) Geol. Soc. Am. Bull., 31, 162-163 (1920).       7. FOSHAG, W. F., Thaumasite (and spurrite) from Crestmore, California: Am. Mineral., 5; 80-81 (1920).       8. FOSHAG, W. F., Plazolite, a new mineral from Riverside, California: Am. Mineral., 5, 183-185(1920).       9. EAKLE, A. S., Jurupaite, a new mineral: Am. Mineral., 6, 107-109 (1921).       10. LARSEN, E. S., AND FOSHAG, W. F., Merwinite, a new calcium-magnesium orthosilicate from Crestmore, California: Am. Mineral., 6, 143-148 (1921).       11. FOSHAG, W. F., Centrallasite from Crestmore, California: Am. Mineral., 9, 88-90 (1924).       12. EAKLE, A. S., Foshagite, a new silicate from Crestmore, California: Am. Mineral., 10, 97-99 (1925).       13. EAKLE, A. S., Famous mineral localities: Crestmore, Riverside County, California: Am. Mineral., 12, 319-321 (1927).       14. TILLEY, C. E., On a custerite-bearing contact rock from California: Geol. Mag., 65, 371-372 (1928).       15. ROGERS, A. F., Periclase from Crestmore near Riverside, California, with a list of minerals from this locality: Am. Mineral., 14, 462-469 (1929).       16. LARSEN, E. S., AND DUNHAM, K. C., Tilleyite, a new mineral from the contact zone at Crestmore, California: Am. Mineral., 18, 469-473 (1933).       17. DUNHAM, K. C., A note on the texture of the Crestmore contact rocks: Am. Mineral., 18, 474-477 (1933).       18. MOEHLMAN, R. S., AND GONYER, F. A., Monticellite from Crestmore, California: Am. Mineral., 19, 474-476 (1934).       19. DALY, JOHN W., Paragenesis of the minerals at Crestmore, Riverside County, California: Am. Mineral., 20, 638-659 (1935).       20. PEACOCK, M. A., On wollastonite and parawollastonite: Am. Jour. Sci., 30, 495-529 (1935).       21. MERRIAM, RICHARD, AND LAUDERMILK, J.. D., Two diopsides from southern California: Am. Mineral., 21, 715-718 (1936).       22. KELLEY, V. C., Notes on mineralization at Crestmore; California: Am. Mineral., 22, 140-141 (1937).       23. PABST, ADOLF, The crystal structure of plazolite: Am. Mineral., 22, 861-868 (1937).        24. MCCONNELL, DUNCAN, The substitution of SiO4- and SO4-groups for PO4-groups in the apatite structure; eflestadite, the end-member: Am. Mineral., 22, 977-986 (1937).        25. MCCONNELL, DUNCAN, A structural investigation of the isomorphism of the apatite group: Am. Mineral., 23, 1-19 (1938).       26. MURDOCH, JOSEPH, AND WEBB, ROBERT W., Notes on some minerals from southern California: Am. Mineral., 23, 349-355 (1938).       27. WOODFORD, A. O., LAUDERMILK, J. D., AND BAILEY, E. H., Treanorite, a new mineral from Crestmore, California: (abstract) Geol. Soc. Am. Bull., 51, 1965 (1940).       28. WOODFORD, A. O., CRIPPEN, R. A., AND GARNER, K. B., Section across Commercial quarry, Crestmore, California: (abstract) Geol. Soc. Am. Bull., 51, 1965 (1940). Abstract of present paper.       NOTES       1 Woodford, A. O., and Harriss, T. F., Geology of Blackhawk canyon, San Bernardino Mountains, California: Univ. Calif. Publ. Bull., Dept. Geol. Sci., 17, 265-304 (1928) (Furnace limestone). Webb, R. W., Evidence of the age of a crystalline limestone in Southern California: Jour. Geol., 47, 198-201 (1939) (Winchester magnesite mine).       2 Dudley, Paul H., Geology of a portion of the Perris block, southern California; Calif. Jour. Mines and Geol., 31, 487-506 (1936).       3 Kindly determined approximately by W. H. Dore of the University of California.       4 Progressive metamorphism of siliceous limestone and dolomite: Jour. Geol., 48, 225274 (1940).      [var:'startyear'='1941'] [Include:'footer.htm']