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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
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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:
Emerson 2 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
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Crystals as large as 1 cm.
|
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Bristol Ferry
N. of light
|
Epidote
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Along quartz veins.
|
| |
Hornblende
|
1 in. crystals in quartz.
|
| |
Muscovite
|
Large plates in pegmatite.
|
| |
Orthoclase
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Pink; white; in dikes.
|
| |
Quartz
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Massive; milky; in veins.
|
| |
Rutile
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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
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In definite, parallel bands;
some 2 in. wide; reds and
greens predominate.
|
| |
Hematite
|
Thin plates.
|
| |
Quartz
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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
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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.
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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.
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LOCALITY
|
MINERALS FOUND
|
REMARKS
|
|
Bald Hill
East slope
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Biotite
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In the porphyry.
|
| |
Magnetite
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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
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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
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In pegmatite.
|
| |
Masonite8 |
|
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Pawtuxet7 |
Quartz
|
Jasper and carnelian in
shales. |
|
Potowomut Neck
(S. side of Greenwich cove)
|
Graphite
|
In shales.
|
| |
Quartz
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Asbestiform; milky; and
ferruginous.
|
|
Spencer Hill
(S. and W. slope)
|
Magnetite
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Probably secondary, penetrating microcline.
|
| |
Quartz
|
In granite
porphyry |
|
1. mi. southwest
|
Augite
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In diabasic dike.
|
| |
Garnet
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Almandite in conglomerate.
|
| |
Labradorite
|
In fair sized xls., in diabasic
dike.
|
| |
Quartz
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Bordering biotite in diabasic dike.
|
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Warwick Neck
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Augite |
Crystals in drift.
|
| |
Graphite |
In shales.
|
| |
Jasper
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In shales.
|
| |
Limonite
|
Secondary after pyrite.
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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.
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LOCALITY |
MINERALS FOUND |
REMARKS |
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LITTLE COMPTON |
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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
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In greenish slate.
|
| |
Quartz
|
Veins cutting limestone.
|
|
Along Sin and Flesh brook |
Actinolite
|
Large needles in horn blende-biotite schist.
|
|
MIDDLETOWN
|
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Easton's Beach
|
Actinolite
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In needles in quartz veins
which penetrate con
glomerate and sandstone.
|
| |
Limonite
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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
|
|
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Mica
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Chiefly biotite.
|
| |
Orthoclase
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In porphyritic granite.
|
| |
Zoisite
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In thin veinlets.
|
|
Purgatory
|
Garnet
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In conglomerate.
|
| |
Magnetite
|
In conglomerate.
|
|
Sachuest Neck and Point
(E. shore)
|
Augite
|
In talc schist.
|
| |
Garnet
|
In conglomerate.
|
| |
Hematite
|
" "
|
| |
Magnetite
|
" "
|
| |
Quartz
|
" "
|
| |
Talc
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In talcose schist.
|
|
NEWPORT
|
|
Bailey's Beach
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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
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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
|
|
JAMESTOWN 12
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 COUNTY 13
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.
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