64 TRANSACTIONS OF THE [Nov. 14, 
That the island is not of a formation to encourage well-drilling 
will appear from the chart and sections, inasmuch as it is nar- 
row and the strata are not bedded at the proper angle to bring 
water from a distance. What is obtained must be surface water. 
And surface water from an area averaging 58,000 persons to the 
square mile, not to mention horses and other animals, could not- 
be expected on @ priori considerations to furnish wholesome 
water. That it actually does not has been shown by the analyses 
of Dr. Waller and other chemists. 
Literature on the Subject. 
‘A Geological History of Manhattan or New York Island,” 
by Issachar Cozzens, Jr. New York, 1843. 
**Report on Fourth District, N. Y. State Survey, Geology of 
the Island,” by Dr. Gale. Page 518. 
Paper on the ‘‘ Geology of Manhattan Island,” by Prof. R. P. 
Stevens. Annals Lyc. Nat. History, Vol. VIII., p. 108. A 
list of unpublished papers is there given. 
H. Credner: ‘‘On the Geology of the Vicinity of New York 
City.” Zeitschrift der deutschen geologischen Gesellschaft, 
XVII., 1865, p. 390. 
Paper on the same, by Prof. J. 8S. Newberry, Pop. Sci. 
Monthly, Vol. XIII., p. 652. 
Mentioned in Prof. Dana’s papers on the ‘‘ Limestone Belts of 
Westchester Co.” Am. Jour. Sci., Vols. XX., XXI., XXII. 
DISCUSSION. 
Pror. W. E. TrRowsrIDGE spoke of the desirability of a topo- 
graphical and geological survey of New York Island before it 
should be entirely covered with buildings. Future questions 
relating to sanitary conditions, underground railways, etc., 
would depend upon facts which could only be determined and. 
preserved by such survey. 
PRESIDENT NEWBERRY briefly described the geological history 
of New York Island and vicinity. He regarded the chiefly 
vertical strata as rendering tunnelling difficult, and water from 
borings impure. 
Prof. D. S. Martin spoke of the definite mineralogical char- 
acter of the New York gneiss, of its continuation southeastward, 
and its evident distinctness from that of the ‘‘ Highlands.” 
Hon. Cuarues P. Daty referred to former features in the 
