The rarallcl Dvlfi-lUlls of Western Xeic York. :-349 



XV. — The rarallel Drift-Hills of Wester)i Kew Yorlc. 



BY LAURENCE JOHNSON', 



Head January 9th, 1882. 



That part of Kew York State which lies between Lake Onta- 

 rio on the north, and Cajaiga and Seneca hikes on the south, 

 presents, in its surface geology, some features of excoptional 

 interest. 



The surface rocks of this region are, for the most part, deeply 

 covered with drift, Avhicli is arranged in a series of parallel hills. 

 Having been reared among these hills, my attention was early 

 directed to their peculiar character ; but, until recently, I had 

 never attempted their systematic study. During the j^ast two 

 or three seasons, however, I have been enabled to renew my 

 acquaintance with the region, and to study it more carefully; 

 the result of my study and observation I now jDresent as a slight 

 contribution to our knowledge of drift phenomena. 



Thongh the surface rocks are generally covered with drift, they 

 are sufficiently exposed in a number of localities to furnish all 

 the data necessary to a correct understanding of their characters 

 and relative positions. 



The lowest rock found in place in this region is the Medina 

 sandstone. This occupies a narrow belt of territory along the 

 shore of Lake Ontario, probably from one to two or three miles 

 in width. In the vicinity of Big Sodus Bay, and also about Port 

 Bay, it lies at or below the level of Ontario, Avhile it rises toward 

 the east and west, appearing at Oswego Falls, twenty-five miles 

 east, and at the lower falls of the Genesee, fifty miles west, 

 fully one hundred feet higher. I invite particular attention to 

 this fact, for, as will appear later, I believe it to be a significant 

 one. 



