﻿Education Department Bulletin 



Published fortnightly by the University of the State of New York 



Entered as second-class matter June 24, 1908, at the Post Office at Albany, N. Y., under 

 the act of July 16, 1894 



No. 489 



ALBANY, N. Y. 



February 15, 191 1 



New York State Museum 



John M. Clarke, Director 

 Museum Bulletin 146 



GEOLOGY OF THE NEW YORK CITY 

 (CATSKILL) AQUEDUCT 



STUDIES IN APPLIED GEOLOGY COVERING PROBLEMS ENCOUNTERED 



IN EXPLORATIONS ALONG THE LINE OF THE AQUEDUCT FROM 



THE CATSKILL MOUNTAINS TO NEW YORK CITY 



BY 



CHARLES P. BERKEY 



PAGE 



Introduction and acknowledg- 

 ment 5 



I General features 9 



Ch. 1 Catskill water supply 



project 9 



2 Problems encountered in 



the project 17 



3 Relative values of differ- 

 ent sources of informa- 

 tion and stages of devel- 

 opment 25 



4 General geology of the 

 region 29 



II Geologic problems of the 



aqueduct 75 



Introduction 75 



Ch. 1 General position of aque- 

 duct line 77 



2 Hudson river canyon .... 81 



3 Geological conditions 

 affecting the Hudson 

 river crossing 



4 Geological features in- 

 volved in selection of site 

 for the Ashokan dam .... 



5 Character and quality of 

 the bluestone for struc- 

 tural purposes . .'. 117 



97 



109 



PAGE 



Ch. 6 The Rondout valley sec- 

 tion 125 



7 The Wallkill .Valley sec- 

 tion 149 



8 Ancient Moodna Valley. . 153 



9 Rock condition of Foundry 

 brook 163 



10 Geology of Sprout brook. 171 



11 Structure of Peekskill 

 creek valley 175 



12 Croton lake crossing 183 



13 Geology of the Kensico 

 dam site 191 



14 Stone of the Kensico 

 quarries 195 



15 The Bryn Mawr siphon. . 201 



16 A study of shaft 13 and 

 vicinity on the New Cro- 

 ton aqueduct 209 



17 Geological conditions 

 affecting the location of 

 delivery conduits in New 

 York city . 215 



18 Areal and structural 

 'geology south of 59th 



street 231 



19 Special exploration zones. 237 



20 The general question of 

 postglacial faulting 271 



Index 277 



