Manhattan Island Geology | Gratacap: Geology of New York City Page 156



	130	GEOLOGY OF NEW YORK CITY

	and Fort George Mr. W. Niven has prospected successfully, adding new species to the island's lists as well as uncovering specimens of unrivaled excellence. The Kingsbridge limestone yields white pyroxene and nests of smoky quartz, beautifully crystallized, with a brown tourmaline tastefully relieved upon the crystalline and snowy matrix of limestone. New localities await the zealous pursuit of collectors, and while the necessary excavations are slowly reducing many geological features, the blasting involved opens up for our temporary gratification new mineralogical treasures. Beyond the limits of the island, in the Bronx, the dolomitic beds may repay exploration, while a mineralized fissure in the limestone at the Jerome Avenue reservoir excavations at 205th to 207th Streets offered sphene and actinolite. -The regions on the island which should be anxiously watched are those to the west, north of 110th Street, and the itinerant mineralogist with a hammer and an observant eye may meet as unexpected and fortunate a chance as rewarded Dr. Wallace Goold Levi-son when he found his most interesting chrysoberyls. Actinolite, the green bladed amphibole, is found as a schist in finely aciculate matted fibres near 221 W. 69th Street (Rev. G. L. Nicholas), also at 78th Street near Amsterdam Avenue, and was taken in West 59th Street at the serpentine area with the " hydrous anthophyllite." A large dike at 128th to 130th Streets, east of Convent Avenue. Adularia, a form of orthoclase, has been found as small white wedges on a granite, with pink orthoclase, from 55th Street and 6th Avenue. Given by Chamberlin at 90th Street and 4th Avenue, Bellevue, Corlear's Hook. Albite, the white soda feldspar, was abundant between 3d and 5th Avenues, from 93d to 101st Streets; a crystal in limestone (calcite) in a crevice in rock at 167th Street and Harlem River (Schernikow), with ripidolite; (pericline form) from 101st Street and Lexington Avenue, 104th Street and 5th Avenue, 176th Street and nth Avenue; (peristerite), glassy with pyroxene, at 109th Street and Amsterdam Avenue; large pericline crystals from 38th Street between 5th and Lexington Avenues;