[Include:'../../../inc/nav.inc']

Volume 12, pages 427-436, 1927

      NOTES ON THE MINERAL LOCALITIES OF RHODE ISLAND PART II. REMAINING COUNTIES 

LLOYD W. FISHER AND CHARLES G. DOLL, Brown University.

      MINERALS NOT INCLUDED UNDER PROVIDENCE COUNTY1

Almandite Lignite Quartz
Apatite Magnetite sand     Amethystine
Asbestus Masonite     Asbestiform
Autunite Monazite     Carnelian
Chabazite Oligoclase     Flint
Chlorite  Olivine     Jasper
Epidote Prochlorite Scapolite
Fluorite Phlogopite Sillimanite
Labradorite Pyroxene Staurolite
    Stilbite
    Zoisite

 

      BRISTOL COUNTY

      The major portion of Bristol County shows sedimentary rocks consisting chiefly of the Rhode Island formation of shales, conglomerates and sandstones. B. K: Emerson2 has mapped the peninsular portion of Bristol Neck as granodiorite. The low cliffs bordering the Taunton River are made up of a coarse grained to porphyritic pink orthoclase granite cut by numerous quartz stringers and pegmatitic granite. The low cliffs of the Mt. Hope Bay region are mainly agatized quartz similar to the Diamond Hill area of Providence County.

      The Bristol area, in the vicinity of Portsmouth Ferry, was famed years ago for the beautiful specimens of amethystine quartz which were found about 1835.

      BRISTOL

LOCALITY MINERALS FOUND REMARKS
Bristol Highlands Limonite After pyrite
  Melanterite White; encrusting shale.
  Pyrite  Crystals as large as 1 cm.
Bristol Ferry N. of light Epidote  Along quartz veins.
  Hornblende 1 in. crystals in quartz.
  Muscovite Large plates in pegmatite.
  Orthoclase  Pink; white; in dikes.
  Quartz Massive; milky; in veins.
  Rutile As needles in quartz.
E. of light  Same as above and Chlorite  Pseudomorphous after biotite.
  Ilmenite In plates in pegmatite.
  Magnetite sand Along strand line.
  Phlogopite In 2 in. orthoclase dike.
  Quartz3  Amethystine variety.
Mt. Hope Bay area  Agate In definite, parallel bands; some 2 in. wide; reds and greens predominate.
  Hematite Thin plates.
  Quartz Massive, in druses.

      KENT COUNTY

      Fringes of sedimentary rocks are found in the east section of this county in contact with a crystalline background which is quite metamorphosed to the west. Minerals are most abundant in the latter areas. The authors have deemed it advisable to include the northern portion of Moosup Valley,which runs northward into Providence County, in this discussion. The rocks of this extreme western area are chiefly Moosup Valley gabbro, Northbridge and Putnam gneisses, quartz stringers, granite pegmatites, granites and various schists.

      TOWN OF COVENTRY

LOCALITY MINERALS FOUND REMARKS
Moosup Valley area Chlorite In large plates
Bennett Hill 2 mi. S. W.4 Epidote Fair sized crystals, near con tact with quartz and schist.
  Hornblende Three in. long.
  Orthoclase Large pink crystals.
  Pyrite Large veins, 4 to 6 in. in width in quartz.
  Pyrrhotite With pyrite.
Between S. Foster and above. Actinolite In schist.
  Apatite Euhedral crystals.
  Biotite Some 8 in. plates.
  Epidote Near contacts.
  Garnet Near contacts.
  Magnetite Octahedral crystals in pegmatite.
  Scapolite Large crystals in the scapo lite-biotite gneiss.
Along Moosup River N. from highway Chlorite In schist with olivine.
  Cyanite5  In schist.
  Ilmenite Platy, lamellar.
  Labradorite Large phenocrysts in gab bro.
  Microcline5 In drift boulders.
  Olivine Large grains in fresh gabbro.
  Serpentine From the olivine.
6 mi. S. W. of Clayville Chlorite Platy on quartz crystals.
  Quartz Massive; milky; smoky, doubly terminated.
  Tourmaline In quartz veins.
N. of W. Greenwich  Magnetite Octahedral crystals.

      EAST GREENWICH

      In the northwestern portion of the town there are some excellent exposures of the granite porphyry of the East Greenwich group.6 The best mineral localities are in this porphyry and are described under Warwick.

LOCALITY MINERALS FOUND REMARKS
Bald Hill East slope Biotite In the porphyry.
  Magnetite Where microgranite cuts dark colored granite.
  Microcline In blue-quartz porphyry.
  Orthoclase  In blue-quartz porphyry and granite porphyry.
  Quartz  Blue; in the blue quartz porphyry.
Bellefont7  Agate In quartz veins.
  Hematite Small plates.
  Graphite In shales.
Drum Rock Hill Epidote In quartz veins.
W. of Apponaug  Garnet In conglomerate.
  Hematite In quartz veins.
  Ottrelite In conglomerate.
 Gaspe Point Magnetite sand With small garnets; strand line.
Norwood Pyrite Large xls. in shale.
Natick Chlorite  These minerals occur in or near the contact of quartzite, conglomerate and arkose. They are also found interstitially on high bluff west of village.
  Epidote
  Garnet 
  Magnetite 
  Ilmenite In pegmatite cutting quartzite.
  Orthoclase In pegmatite.
  Masonite8  
Pawtuxet7 Quartz Jasper and carnelian in shales.
Potowomut Neck (S. side of Greenwich cove) Graphite In shales.
  Quartz Asbestiform; milky; and ferruginous.
Spencer Hill (S. and W. slope) Magnetite Probably secondary, penetrating microcline.
  Quartz In granite porphyry
1. mi. southwest Augite In diabasic dike.
  Garnet Almandite in conglomerate.
  Labradorite In fair sized xls., in diabasic dike.
  Quartz  Bordering biotite in diabasic dike.
Warwick Neck  Augite Crystals in drift.
  Graphite In shales.
  Jasper In shales.
  Limonite Secondary after pyrite.

   

      NEWPORT COUNTY

      The geology of this county is quite varied since both igneous rocks and sediments occur. The eastern portion of the county shows chiefly sedimentary rocks with some metamorphics near the northern border. Along the coast line from Tunipus Beach to Sakonnet Point igneous rocks predominate, chiefly a porphyritic granite. Wave action has leached out most of the femic minerals leaving large pits in the rocks.

LOCALITY MINERALS FOUND REMARKS
LITTLE COMPTON
Warren's Point a type locality  Epidote  Well developed xls. along aplite dike.
  Hornblende Along aplite dike.
  Ilmenite  In plates in aplite which cuts granite.
  Orthoclase Large pink xls. in granite.
  Quartz  Smoky; milky; in aplite.
Sakonnet Point Apatite Euhedral xls. in minette.
Tunipus Beach Chlorite Plates on quartz.
TIVERTON
Near Four Corners Pyrite In greenish slate.
  Quartz Veins cutting limestone.
Along Sin and Flesh brook Actinolite Large needles in horn blende-biotite schist.
MIDDLETOWN
Easton's Beach Actinolite In needles in quartz veins which penetrate con glomerate and sandstone.
  Limonite In argillaceous mica. schist, after pyrite.
  Hornblende Same as actinolite.
  Magnetite Same as limonite.
  Rutile Same as actinolite.
Paradise (Hanging Rock) Chlorite Same as actinolite.
  Magnetite  
  Mica Chiefly biotite.
  Orthoclase In porphyritic granite.
  Zoisite  In thin veinlets.
Purgatory Garnet In conglomerate.
  Magnetite In conglomerate.
Sachuest Neck and Point (E. shore) Augite In talc schist.
  Garnet In conglomerate.
  Hematite  " "
  Magnetite  " "
  Quartz  " "
  Talc   In talcose schist.
 NEWPORT
Bailey's Beach Feldspars Large xls. in granite.
Bishop Rock Garnet Euhedral xls. in conglomer ate.
 Brenton's Cove Fort Adams, E. side Calcite Xls. in argillaceous mica schist.
  Quartz In mica schist, iron stained.
  Serpentine In mica schist.
  Chlorite These minerals occur in a coarsely porphyritic granite.
  Magnetite
  Oligoclase
  Orthoclase
  Titanite
  Zoisite
Miantonomah Hill (S. sideof Coddington Cove)  Chlorite  Large plates in quartz veins in conglomerate.
Ochre Point  Calcite In shales.
  Serpentine Serpentinous shales.
  Epidote Transition product in epi dote-chlorite schist.
  Talc In epidote-chlorite schist.
  Ottrelite     "       "      "
 PORTSMOUTH9
Near old coal mine, west shore Calcite In shales.
  Chalcopyrite   " "
  Garnet Near contacts with schist.
  Graphite In shales. Graphitic anthracite.
  Ottrelite10 In metamorphosed shale.
  Quartz Fibrous, in veins.
  Prochlorite  In schist.
  Staurolite In schist.
  Siderite In quartz veins cutting graphitic shales.

  

      NEW SHOREHAM (Block Island)

LOCALITY MINERALS FOUND REMARKS
South shore Almandite In pegmatite.
  Beryl5   "     "
  Clay iron stone Concretionary in shale.
  Magnetite With garnet sands.
  Limonite In shales.
  Kaolin In low bluffs.
  Pyrite With the above.
  Monazite11 In sands.
  Sillimanite  
  Zircon  

  

      JAMESTOWN12

      The island of Conanicut on which Jamestown is located is made up chiefly of a rather fissile, greenish shale accompanied in the southern portion by altered shales and granites. Both types are cut by basic dikes.

LOCALITY MINERALS FOUND REMARKS
Hull's Cove Apatite In euhedral xls. in minette dike. Same as at Sakon net Point.
  Biotite In minette dike, n. and s. end of island.
  Titanite In minette dike.
  Zircon   "     "
Mackerel Cove (W. side of cove) Siderite Numerous xls. in hornfels.
Potter's Point  Albite In phyllitic shale.
  Graphite    "     "
  Hematite    "     "
  Muscovite    "     "
  Tourmaline Fair sized euhedral xls.
South shore Calcite  
  Chlorite From biotite.
  Oligoclase South shore, eastern por tion of Island.
  Orthoclase From eastern part of Island
  Magnetite     "    "
  Quartz      "    "
  Sericite Platy on feldspars.
  Titanite Euhedral xls. in feldspars.
West shore midway between north and south ends of the island. Epidote In altered shales.
  Garnet     "     "
  Ottrelite     "     "
  Staurolite     "     "

      WASHINGTON COUNTY13

      This county is quite important geologically because of the famous Westerly granite quarries which are worked extensively in the towns of Westerly and Bradford (formerly Niantic). The Westerly granite cuts the Sterling granite gneiss and is in places cut by an olivine diabase dike which is well shown in the Smith quarry, Westerly, and at White Rock 4 miles north of Westerly. The general geology and mineral localities of all districts are somewhat similar. Locally there are pegmatitic phases of the Westerly and these are the best mineral repositories. A few of the prominent localities will be described.

LOCALITY MINERALS FOUND REMARKS
CHARLESTOWN
Kenyons Sillimanite  In schist; locally distributed.
Quonochontaug Biotite In large plates in an orbi cular granite.
HOPKINTON
1/2 mi. N. of town on Nooseneck Hill road Biotite In Sterling granite-gneiss.
  Chlorite
  Ilmenite 
  Orthoclase
  Quartz
 NORTH KINGSTOWN
Hamilton Calcite Perfect xls. in sandstone.
SOUTH KINGSTOWN
Wakefield Ilmenite Large plates in pegmatitic phase of Westerly.
Watch Hill to Point Judith Magnetite With garnet in sand.
Usquepaug  Molybdenite In pegmatitic granite.
NARRAGANSETT
Tower Hill Autunite14 In pegmatitic phase.
  Orthoclase In pegmatitic phase, large crystals.
     
WESTERLY
Smith Quarry, S. E. of Westerly, also in Smalley Quarry, N. of Westerly  Allanite15 In granite unless otherwise noted.
  Apatite  
  Beryl  
  Biotite  
  Calcite Along contact of the olivine diabase dike and granite.
  Chabazite Along contact of olivine diabase.
  Natrolite  
  Stilbite  In fractures.
  Cyanite  
  Epidote  
  Fluorite On fracture planes: purple cubes.
  Ilmenite  
  Molybdenite  
  Microcline  
  Muscovite  
  Pyrite  
  Oligoclase  

 

      The largest feldspar crystals, simple, or twinned according to the Carlsbad law are found in the coarse phase of the Westerly granite in the Sullivan quarry, Bradford. In most cases noted the domatic faces of the crystal, which may be a foot or more in size, are coated with biotite which is being chloritized. Smoky and transparent quartz crystals are found in abundance in the same locality and these reach a size of 4 inches. The Sullivan quarry is an ideal mineral collecting ground.

      OTHER AREAS OF MINOR IMPORTANCE

      The writers have visited all the important or promising mineral localities of the State during the past field season and some regions of minor importance are included. Minerals from these areas are listed here with the finder's name, those not so listed were found by the senior author.

      Burrillville-Amethystine quartz and kaolin. (J. P. Beatty).
      Chepachet-Magnetite in pegmatite. (A. C. Hawkins).
      Albite-pericline in chlorite. (A. C. H.).
      Centredale-Quartz crystals in green schist 16
      Glocester (Durfee Hill)-Epidote, molybdenite, pyrite, pyrrhotite 17 
        Harmony (Steere Hill)-Ilmenite in pegmatite
      Hughesdale-included under Johnston.

      JOHNSTON

      The general locality of this area is much the same as discussed under Ochee Springs and Violet Hill, Manton Avenue, Providence, in the first part (see footnote 1). Minerals found in Johnston outside these two localities, are: Actinolite, ankerite, calcite, chalcedony, chalcopyrite, pyrite, hornblende, tremolite, steatite, serpentine, and epidote. Magnetite in good crystals in chlorite Schist (A. S. Packard).

      Lime Rock-Scolecite in calcite. (J. P. Beatty). 
      Pascoag-Epidote and tourmaline. (A. C. Hawkins).
       Primrose (Premisy Hill)-Magnetite in arkose. (A. C. H.). 
      Richmond (Tunk Hill)-Actinolite in schist.
      Snake Den-Chalcocite, epidote, fluorite (M. Bowe), garnet and malachite.

      A gold-mine prospect was worked in this locality where a diabasic dike cuts the granites and schists. Cyanide vats and sluice boxes are still visible. A local chemist is authority for the statement that the locality is reported to have shown a trace of platinum in the debris.

      Tarkiln-Quartz and magnetite in pegmatite.

     NOTES

      1 L. W. Fisher and E. K. Gedney: Notes on the Mineral Localities of Rhode Island. Am. Mineral., 11, No. 12, pp. 334-340, (1926.)

      2 B. K. Emerson: Geology of Massachusetts and Rhode Island. U. S. G. S. Bull. 597. See map.

       See also A. C. Hawkins, and C. W. Brown: Basic Rocks of Rhode Island. Their correlation and relationship. Bull. Geol. Soc. Amer, 26, pp. 92-93.

      3 The best locality for amethystine quartz located by the writers is about 100 yards east of the ferry near a spring. It is found in a disintegrating granite. Some excellent blue crystals, four to six inches in length, are in the Museum of the Department of Geology. These were shown at the Centennial in Philadelphia in 1876 by the Providence Franklin Society.

      4 This is the old South Foster Gold mine locality which is said to have produced gold, chiefly from pyritiferous-quartz veins. Four open pits filled with water were visible at the time of the study. The foundations of a rather large stamp mill still stand.

      5 Not found by the writers but reported from specimens in the departmental museum. Specimens collected by C. W. Brown and others.

      6 B. K. Emerson and J. H. Perry: Green schists and associated granites and porphyries of Rhode Island U. S. G. S. Bull 311, p58 (1907).

      7 These towns are just north of the Pawtuxet River which divides Kent and Providence Counties.

      8 The mineral could not be found in place although boulders with plates of the chloritoid mineral were found. The old locality has been built over. See Charles Jackson; Report on the Geological and Agricultural Survey of Rhode Island, 1840; and The Geology of Rhode Island; Providence Franklin Society, 1887, p91.

      9 For general geology see Geology of Aquidneck Island. N. S. Shaler. Amer Nat., Vol. 6. 1872.

      10 Specimens labeled Newportite in the Roger Williams Park Museum, Providence, are probably identical with ottrelite. Newportite is mentioned by S. B. Robinson in Catalogue of American Mineral Localities, 1832; by Horace F. Carpenter, Mineral Catalogue of New England Localities, 1860.

      11 From specimens in R. W. Park Museum donated by A. P. Watt.

      12 For Geology see L. V. Pirsson, Geology of Conanicut Island. Amer Jour. Sci., 3rd Ser., Vol. XLVI, pp. 363-378.

      13 E. K. Gedney, joint-author of Providence county localities, assisted in this area.

      14 Found by C. W. Brown. Radio-activity determined by Gedney.

      15 See footnote 5.

      16 A. C. Hawkins: Quartz crystals from Centredale, Rhode Island. Am. Mineral., Vol. 3., No. 1, pp. 1 and 2.

      17 This is also an old gold mine locality.

[var:'startyear'='1927'] [Include:'footer.htm']