﻿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 Congress of July 16, 1894 



No. 485 ALBANY, N. Y. December 15, 1910 



New York State Museum 



John M. Clarke, Director 

 Museum Bulletin 145 



GEOLOGY OF THE THOUSAND ISLANDS REGION 



ALEXANDRIA BAY, CAPE VINCENT, CLAYTON, GRIND- 

 STONE AND THERESA QUADRANGLES 



BY 



H. P. CUSHING, H. L. FAIRCHILD, R. RUEDEMANN & 

 C. H. SMYTH ]R 



INTRODUCTION 1 



The field work on which the accompanying report is based was 

 done during the field seasons of 1906, 1907 and 1908. The dis- 

 trict was chosen for work chiefly on the recommendation of 

 Professor Smyth, and work was begun by the writer with the 

 understanding that we were to collaborate in doing it. Unfortu- 

 nately this plan failed of realization, owing to Mr Smyth's inability 

 to take the field, so that his actual participation in the work was 

 limited to a portion of the season of 1908, during which he 

 mapped the major portion of Wellesley island. 



Dr Ruedemann assisted in the mapping of the southern part 

 of the Theresa quadrangle during two weeks of the season of 

 1907 and in 1908, mapped Cape Vincent and the southern half of 

 Clayton. The remainder of the areal mapping is the writer's 

 contribution, comprising the Theresa, Alexandria and Grind- 

 stone sheets (with the exception of Wellesley island) and the 

 north half of Clayton. 



Note. The photographs credited to Ami and Ulrich are published by 

 permission of the Directors of the Geological Surveys of Canada and of 

 the United States. 



1 By H. P. Cushing. 



