BOTANICAL EVALUATION OF THE GOAT ISLAND COMPLEX, NIAGARA FALLS, NEW YORK
P. M. Eckel
Buffalo Museum of Science
1020 Humboldt Pkwy
Buffalo, NY 14211 U.S.A.
www.buffalomuseumofscience.org

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GLACIERS
During the last (Wisconsin) ice age, the region of the vicinity of Niagara Falls was covered by the Labradoran ice sheet, only the most recent in a sequence of the advance and retreat of such continental glaciers throughout the Pleistocene. The last glacier, like the previous ones, mechanically removed all soil, and hence all vegetation on the areas over which it passed. The present flora, then, totally derives from vegetated areas south and west of the ice front. The Niagara region was essentially free of glacial cover around 12,300 years ago, with the establishment of Lakes Erie and Ontario (Glacial Lake Iroquois) (Tesmer, 1981).

"The surface of the rock, on which the deposit forming Goat Island is made, is smoothed and scratched, as are the surrounding surfaces, both in the rapids and on either bank of the river" (Hall, 1843), testifying to the passage of the continental ice mass over the area. Porter (16 Ann Rep Comm, 1900) also reported glacial markings on the exposed bedrock of Goat Island. In a popular account of the geology of the area, Tiplin (1988) indicated that at the east end of Goat Island and the Three Sister Islands, the visible ridges are "roches moutonnees": eroded pre- or inter-glacial ridges formed first by river-erosion and subsequently modified, "polished," by the glacial ice-mass.

Much of the aspect of the bedrock on Goat Island, once exposed in the southeastern portion of that island, is hidden beneath the topsoil deposited there in 1911 (28 Ann Rep Comm, 1912).

With the gradual retreat of the ice sheet came a period of time when the hydrology of the Great Lakes watershed system underwent many changes as the watershed rid itself of the mass of water liberated by the melting glacier. Since details of this complex history of shifting drainage patterns and volumes cannot be confidently related to conditions useful in explaining vegetation patterns in the Goat Island complex, the reader is directed to the extensive literature available on this subject, conveniently summarized by Otis (1982).

Between one quarter and one half of the surface sediment on Goat Island is composed of glacial deposits (Kindle & Taylor, 1913).