In the summer of 1888, gemologist George F Kunz announced to the New York Times that the New York Mineralogical Club would be making a field trip to the Fort George area of Manhattan Island on Saturday, June 30th (Times, 1888). The mineral club was still in its infancy, but already had established a fairly vigorous program of field collecting.

Mineral collecting, when sites afforded themselves, was a convenience in late 19th Century New York City. Mass transit made access easy. Kunz remarked that the club members would take the elevated trains to 125th Street then switching over to the adjacent cable cars to the collecting site. The Club offered an open invitation to “any persons of suitable standing, either ladies or gentlemen” to accompany the members for an afternoon of collecting.

Fort George takes its name from one of three Revolutionary War era forts in northern Manhattan which were constructed by the Patriot army for the final defense of New York City in 1776. The fort, a hodge-podge of earthworks and a small wooden blockhouse, was erected atop what was then called Laurel Hill where modern day Fort George Avenue loops to connect Amsterdam Avenue with St Nicholas Avenue. In Mid November, 1776 the fort fell to the besieging British army, but not before its small garrison bought enough time for Washington's main force to escape into northern New Jersey. The British strengthened the fortifications, and during the remainder of the war it was a vital defense against invasion by the Patriot army. Soon after the war's end in 1783, the position was abandoned.


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The area remained farmland for the next hundred years, and was still largely open ground when the Club visited in 1888.

The expedition to the northern reaches of Manhattan was successful, and a few months Kunz filed a report of their discoveries with the New York Academy of Sciences (Kunz, 1888c). Among the species they observed were:

Almandine crystals of almandine to 0.25 inches in diameter were found; Kunz noted that they were “very bright” and that “one beautiful flattened crystal of transparent garnet was found between plates of muscovite”.

Beryl - some of the largest crystals of beryl ever found on Manhattan Island were recovered at Fort George, found in what Kunz described as a “coarse granite.” The largest was a only half a crystal, split down the c-axis, but measured 4 inches in diameter. Another specimen was 3 inches wide and 2.5 inches long, while others ranged to an inch in diameter and 2 inches long. One of the more interesting specimens was an 8 inch by 10inch piece of matrix studded with 17 crystals, measuring from 0.25 inch to 1 inch in diameter.

Clinochlore var. “ripidolite” The “ripidolite” was observed associated with titanite.

Columbite – Kunz reported finding two black crystals of columbite, the first such discoveries on Manhattan Island. The largest of the two measured one inch long and 0.25 inches wide, embedded in orthoclase. “The prismatic faces are quite distinct, but the terminal planes are imperfect from breaking.”

Epidote– crystals up to 1.5 inches long and 0.5 inches in width. Whitlock (1903) notes that in addition to epidote occurring in “small brilliant crystals” it also occurs in granular masses.

Ilmenite var.Washingtonite Fort George produced “plates two inches across and one eighth inch thick”embedded in orthoclase. “Washingtonite” was an ill-defined variety originally described from Connecticut.

Muscovite The crystals observed by Kunz, on a matrix of orthoclase, were 10 inches across. Whitlock (1903) notes “green rhombic crystals” or muscovite in a pegmatite vein associated with quartz and orthoclase.

Orthoclase– a 6 inch wide broken crystal, devoid of termination was found.

Rutile – as prismatic crystals, terminated by a simple pyramid, up to 5cm long and 3mm in diameter. Kunz noted that the faces were “bright, although not polished” Gratacap (1909) describes the Fort George rutiles as “channeled square prisms with scapolite and prochlorite”. (Prochlorite is an obsolete term for clinochlore.)

Titanite The titanite crystals from Fort George were mostly yellow in color, although Kunz noted that a few were light green. The crystals were small, measuring up to 0.25 inches wide. A year later, the Transactions of the New York Academy of Sciences (19 November 1888) contained a brief note that “Mr. Kunz also announced that among the yellow titanites found by Mr. Niven on the site for the Old Men's Home, at Fort George, N. Y. City, was one piece which Mr. Niven had had cut into a small gem, weighing about 1/8 carat, and quite brilliant, although hardly equal to the same material from Tavetschthal, Switzerland.” Whether this specimen was recovered at the same time as the examples described by Kunz is unknown.

Additional Species

The following species were reported by other writers, but were not observed as part of the 1883 field trip by the New York Mineralogical Club:

Actinolite Whitlock (1903) noted the occurrence of actinolite associated with quartz and torumaline.

Apatite Gratacap (1909) mentions the occurrence of an apatite-group mineral as “good dark dark crystals in quartz”.

Autunite? Chamberlin (1888) lists autunite (meta-autunite?) as an uncertain report for Fort George.

Cordierite Chamberlain (1888) reports that a specimen originally found by mineral dealer William Niven was identified by William E Hidden as “iolite.” The cordierite was altered to “pinite” (see below). The specimen was “greyish green” and measured 1 x 1.5 inches, and was “divided into basal sections”.

Grossular reported as occurring as “light colored garnet, attractively set in white feldspar and glistening silver mica” by Gratacap (1909). Whitlock (1903) mentions “grossularite” but without details.

HornblendeWhitlock (1903) notes the occurrence of hornblende associated with quartz and tourmaline.

Malachite occurring as “radiating tufts”, malachite was reported by Whitlock in the pegmatite veins.

Oligoclase Whitlock (1903) notes the occurrence of oligoclase as “moonstone” associated with quartz.

“Pinite” is an obsolete term for a physical mixture of silicate-based alteration products. It was reported by Chamberlin (1888) as occurring in a specimen of highly altered cordierite.

Quartz” Gratacap (1909) reported smoky quartz from Fort George. Chamberlin (1888) notes that Niven reported by massive and crystals of smoky quartz.

Scapolite Chamberlin (1888) notes that scapolite was reported from Fort George, but without much detail. Reported by Gratacap (1909).

Staurolite Kunz (1888) supplied a brief notice to the New York Academy of Sciences of the discovery of staurolite at Fort George: “in a mica schist on the site of the Old Men's Home, Fort George, staurolite in brilliant dark brown doubly-terminated crystals, one-third of an inch long.” (Kunz 1888a)

Stilbite Occuring as “sheaflike aggregates”, Whitlock (1903) notes stilbite from the locality.

TourmalineWhitlock (1903) mentions black tourmaline crystals in a pegmatite vein associated with orthoclase at Fort George.

Wollastonite Chamberlin (1888) reports wollastonite without providing any details.

Zircon zircon occurring as “tiny crystals” associated with quartz are reported by Whitlock (1903).

Postscript:

A few years after the New York Mineralogical Club's jaunt to the site, Fort George underwent a radical transformation. In 1895 the site was developed as an amusement park. While Fort George Amusement Park would never rival the famed Coney Island, it was the largest in Manhattan. Two devastating fires in 1911 and 1913 ravaged the park, which never fully recovered. The park became dominated by dance halls, sleazy taverns, and tawdry entertainments. Kunz, as president of the American Scenic and Preservation Society (his other great passion) agitated for the amusement park to be converted into open parkland for the public; instead, the George Washington High School was constructed there in 1920.

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Bibliography

Gratacap, Louis Pope
Geology of the City of New York: With Numerous Illustrations and Maps
New York, 1909

Chamberlin, B B
The Minerals of New York County, Including a List Complete to Date
Transactions of the New York Academy of Sciences
Vol. 7 (1888)

Kunz, George F (1888a)
“Regular Business Meeting” 1 October 1888
Transactions of the New York Academy of Sciences
Vol. 8, 1889 (p3)

Kunz, George F (1888b)
“Stated Meeting” 18 November 1888
Transactions of the New York Academy of Sciences
Vol. 8, 1889 (p21)

Kunz, George F (1888b)
Minerals From Fort George, New York City
Transactions of the New York Academy of Sciences
Vol. 7, 1888 (p49)

NY Times 1888 “Mineralogists' Summer Outings”
New York Times 24 June 1888.

Whitlock, H P
List of New York Mineral Localities
New York State Museum Bulletin 70
Albany, 1903