Excerpt from The Configuration of the Rock Floor of Greater New York Accurate maps - The early importance of Manhattan Island in com mercial and economic lines and its entry upon great engineering enter prises which require a penetration of the rock floor have greatly facilitated the work of the structural geologist within the area. As early as 1821 the city was laid out, and the gridiron of numbered streets and avenues has not only been responsible for a precision and accuracy of the early maps, rarely obtainable elsewhere, but has given to even casual geological observations unusual value. Randall's map of the island, submitted in sections between the years 1811 and 1821, now preserved in'the Office of the commissioner of public works, gives the precise locations of all the old farms in relation to watercourses and topography. It comprises four volumes of 92 sheets of map, size 25 by 37 inches, on scale of 100 feet to the inch. General Viele's map, on the scale of feet to the inch, was published in 1874, 'z and is based upon Randall's map. It shows the original shore line of the island, the mainland, the drainage system, the topography, and the location of each exposure south of Manhattanville, all superimposed upon the gridiron of streets and avenues. The accuracy of this map has been abundantly attested by engineers, real estate men, and others, who habitually use it, and, so far as the exposures of rock are con cerned, it has been tested by the writer, both by comparison with the early reports of geologists upon Manhattan Island and by examination in the field. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.