Portland, Middlesex Co., Connecticut, USA

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Known as "Quarrytown" primarily for the large "brownstone" quarries (aeolian arkosic sandstone of the Portland Formation) near the Connecticut River in the western part town, Portland is also host to the most famous pegmatite quarry in the area - the Strickland Quarry. Coordinates are for the downtown intersection of State Routes 17A and 66 in the west, which is far removed from the pegmatite quarries farther east.

European settlers arrived in the 1690s, attracted to the blocks of brownstone along the riverbank. Originally Portland was part of Middletown and was known as East Middletown. In 1767 it became the separate town of Chatham. In 1841, when it separated from the eastern part of Chatham, it changed its name first to Conway then to Portland (because of the fame of quarries in that English town) (The remainder of Chatham changed its name to East Hampton in 1915.)

The bedrock geology is split between continental sedimentary rocks in the west, part of the Mesozoic Hartford Basin of the Newark Supergroup and mostly metaplutonic, metavolcanic and metasedimentary metamorphic rocks of the Ordovician Bronson Hill terrane in the east. These terranes are separated by the Eastern Border Fault of the Hartford Basin. Much of the Bronson Hill terrane rocks in town are mixed schists, calc-silicate rocks, and minor quartzites of the Collins Hill Formation, and its metavolcanic member, which are present just east of the Eastern Border Fault. Farther east the bedrock is mostly metaplutonic Glastonbury Gneiss, which crops out as far south as Great Hill Pond. A thin sliver of Devonian Maromas Granite Gneiss is also present.

Portland lies within the Middletown Pegmatite District, and a swarm of Permian pegmatite dikes lies just east of the Eastern Border Fault, mostly within the Collins Hill Formation, but some further east in the Glastonbury Gneiss. These were heavily quarried from the north at the Glastonbury town line and just east of State Route 17 (particularly the long-lived Hale Quarry) southward onto Collins Hill, which hosted the famous Strickland Quarry and Cramer Mine, where most of Portland's diverse mineralogy originates. Most pegmatite specimens just labeled "Portland" are likely from there, although the small Walden Gem Mine and Case Quarries produced many specimens also. Sharply formed and deeply colored aquamarines hail from the small Pelton's Quarry. Unquarried pegmatites can still be easily seen along State Route 66 in the Riverdale section just north of the Connecticut River in the area known as "The Ledges".

Mineral List

Mineral list contains entries from the region specified including sub-localities

Actinolite Albite var: Cleavelandite var: Oligoclase var: Peristerite 'Allanite' Almandine Analcime Anatase Anglesite Annite Aragonite Arsenopyrite Autunite Bavenite Bertrandite Beryl var: Aquamarine var: Goshenite var: Heliodor var: Morganite 'Biotite' Bismite Bismuthinite Bismutite Bismutoferrite Bityite Calcite Cassiterite Chalcopyrite 'Chlorite Group' Clinozoisite 'Columbite' Columbite-(Fe) 'Columbite-Tantalite' Cookeite Cordierite Crandallite Cuprobismutite

Dickinsonite-(KMnNa) Diopside Elbaite Eosphorite Epidote Epsomite 'Feldspar Group' Ferrimolybdite Fluorapatite var: Mn-bearing Fluorapatite Fluorite Foitite Gahnite Galena 'Garnet' Gobbinsite Goethite Graphite Greenockite Grossular 'Gummite' Gypsum Hematite Heterosite Hexahydrite ? 'Hornblende' Hureaulite Ilmenite Ishikawaite Kaolinite Kyanite Lacroixite Lepidolite Liandratite 'Limonite' Lithiophilite Löllingite Magnetite 'Manganese Oxides'

'Manganese Oxides var: Manganese Dendrites' Melanterite Meta-autunite Metatorbernite Microcline var: Amazonite Microlite Group Mitridatite Molybdenite 'Monazite' Monazite-(Ce) Montebrasite Montmorillonite Muscovite Opal var: Opal-AN 'Perthite' Petalite Phenakite Phlogopite Phosphuranylite Pickeringite 'Pinite' Pollucite 'Prochlorite' Purpurite Pyrite Pyrochlore Group Pyrrhotite Quartz var: Amethyst var: Chalcedony var: Citrine var: Milky Quartz var: Rock Crystal var: Rose Quartz var: Smoky Quartz Reddingite Rhodochrosite

Rutile Samarskite-(Y) 'Scapolite' Scheelite Schorl Scorodite Siderite Sillimanite Spessartine Sphalerite Spodumene var: Kunzite Staurolite Sulphur Tantalite-(Mn) 'Tapiolite' Thorogummite Titanite Topaz Torbernite 'Tourmaline' 'var: Indicolite' 'var: Rubellite' 'var: Verdelite' 'var: Watermelon Tourmaline' Triphylite Triplite Uraninite Uranophane 'Uranpyrochlore (of Hogarth 1977)' Vivianite Wodginite Wollastonite Xenotime-(Y) 'Zinnwaldite' Zircon var: Cyrtolite Zoisite

191 entries listed. 111 valid minerals.

Localities in this Region

USA Connecticut Middlesex Co. Portland Andrews Quarry (old Hale Quarry; Grandfather Andrews Quarry) Appletree Lane Bordonaro Quarry Case quarries Collins Hill Carr Brook Waterfall Hale-Walker prospects Strickland pegmatite (Strickland-Cramer Quarry; Strickland-Cramer Mine; Strickland-Cramer Feldspar-Mica Quarries) Schoonmaker Mine (Cramer Mine)

USA Connecticut Middlesex Co. Portland Collins Hill Strickland pegmatite (Strickland-Cramer Quarry; Strickland-Cramer Mine; Strickland-Cramer Feldspar-Mica Quarries) Strickland Quarry (Eureka Quarry) Unnamed building stone quarry Gotta-Walden Prospect Gotta-Wannerstrom Quarry Hale Quarry (Andrews Quarry; Glastonbury Quarry) Pelton's Quarry Penfield Quarry (Oak Leaf Quarry) Synnott Quarry Walden Gem Quarry

References