44 ' NEW YORK STATE MUSEUM 



distance beyond the map limits existed at an elevation of from iioo 

 to 1 1 50 feet. The clay beds are best shown along the canal feeder 

 between 2 and 3 miles northwest of Forestport and also along 

 Crystal creek and Cold brook. These and probably other water 

 bodies were doubtless formed behind the ice front or morainic 

 -deposits acting as a dam on the west. 



Sand deposits 



Extensive deposits of sand, frequently associated with gravel, 

 and more or less distinct from the kame-moraine material, occur 

 within the district. These sand areas, which are locally called 

 ■*' sand flats," for the most part lie east of the Precambric Pale- 

 ozoic boundary line. Many times these sands show no sign of strat- 

 ification while at other times a crude stratification can be made out. 



The largest sand covered area lies between Alder Creek, Enos and 

 Myers hill and northwestward beyond the limits of the map. Over 

 this whole region occupying about 50 square miles scarcely any 

 Tock exposures can be found except along the principal stream 

 bottoms. 



Sand flats are also found to the east, southeast and south of Enos. 

 The most interesting sand flat is the one lying between West 

 Canada and Black creeks. The topographic map shows it as a 

 flat topped bench or terrace. The sand is here from 50 to 100 

 feet deep and is underlain by the extensive clay beds above de- 

 scribed. Sand flats at lower levels also occur in the vicinity of 

 Trenton Falls. 



The problem of the classification and origin of these sands is a 

 difficult one. It is evident from their varying character and dis- 

 tribution that no single explanation will account for them all. In 

 a general way at least the writer offers the suggestion that the 

 unstratified sands were largely deposited as simple drift or morainic 

 material, while the cruder stratified portions were partly the 

 result of overwash deposits from the edge of the ice and the moraine, 

 and partly delta deposits formed where the larger streams emerged 

 from the high Precambric land to the northwest. 



The distribution of the sand flats, their absence from the Pre- 

 cambric highlands, the steep slopes of the stream beds and the 

 presence of much sandy drift over the Precambric highland, and 

 the ice and moraine barrier to the southv/est causing the formation 

 of the lakes and acting as a general obstruction to drainage would 

 altogether strongly argue for the delta method of origin of much of 

 the sand. Thus the sand overlying the clay between West Canada 



