CLAYS or NEW YOKK 607 



Botli Dana and Merrill consider Long Island sound to be of 

 preglacial origin. Tlie former calls attention to a channel in the 

 southern part of the sound, which probably was that of a river 

 draining Connecticut in preglacial times, and which emptied into 

 Peconic bay. The latter points to the absence of till along the 

 north shore of Long Island where the sound is wide, as evidence 

 of the fact that most of the drift was dropped into the sound by 

 the ice in its passage across it. 



On the other hand HoUick considers that Long Island sound 

 was dry land till the glacial period, and that the continental glacier 

 upon its arrival on the Connecticut shore plowed up the material 

 from the space now occupied by the sound and pushed it ahead to 

 form the range of .hills along the northern part of Long Island. 

 It seems to the writer however that the facts do not support this 

 theory. If we suppose the northern range of hills to be composed 

 of material pushed up out of the area now occupied by the sound, 

 it should everywhere show signs of disturbance. This it does not 

 do. The high hills of sand and gravel at Port "VYashington for 

 example show no signs of disturbance. 



Mention should be made of a yellow gravel formation. This is 

 found almost everywhere on Long Island, and sections in the rail- 

 way cuttings frequently show a thickness of 30 or 40 feet. 



Staten Island clays 



The chief outcrops of clay on Staten Island are at Kreischerville, 

 Greenridge and Arrochar. Besides the clay there are several sand 

 beds known as " kaolin." 



In many instances the clays and overlying yellow gravels have 

 been much disturbed by the passage of the ice over them, and in 

 some cases the sections show overthrown anticlines, as on the finger- 

 board road at Clifton. 



W. Ivi-eischer informed me that the clay at Kreischerville occurs 

 in isolated masses or 'pockets in the yellow gravel and sands. If 

 such is the case, f.iid if these beds, as is usually supposed, are a 



