Quoted at the beginning of “The Survey Area” that defines the geology of NYC, as appears in the Reconnaissance Soil Survey, a collaborative project of US Dept. of Agriculture, Natural Resources Conservation Service, New York City Soil and Water Conservation District, and Cornell University Agricultural Experiment Station.

New York City Soil Survey Staff. New York City Reconnaissance Soil Survey. Staten Island, NY: United States Department of Agriculture, Natural Resources Conservation Service, 2005, p. 3.