SURFACE GEOLOGY. G 5 . 27 



1/ in diameter, nearly all water- worn into a rudely spherical 

 shape, and imbedded in a matrix of coarse sand and fine 

 gravel. A few small bowlders of limestone looking like 

 Lower Helderbnrg have probably come from the valley of 

 the Mohawk, the nearest place of outcrop. I could rind no 

 conglomerate nor crystalline rocks. 



Terraces and mounds : — The wide valley of the Susque- 

 hanna is filled with Drift trash, generally occurring in broad 

 level terraces, but occasionally in huge conical mounds. 



Opposite Susquehanna Depot on the north bank of the 

 river some long sharp ridges 40' to 50' high, run parallel to 

 the general course of the river. 



Many angular fragments of local rock are seen in the Drift 

 above Lanesboro, 3 miles from Susquehanna Depot. 



Clay in considerable quantity is often mixed with the 

 rock fragments of the Drift. This is well shown in the 

 Ararat Summit cut on the Jefferson Branch railroad (2023' 

 A. T.) Here about 35' of genuine Drift is seen and no bot- 

 tom reached. 



Pure clay deposits occur in places, caused in some man- 

 ner by the ice. 



Two miles above the mouth of Starrucca creek, is a dam 

 of pure clay 75 feet high extending entirely across the ancient 

 channel of the stream, which has been compelled to cut 

 around it through the solid rock on its west bank. This 

 clay bank is extensively worked for brick making. In the 

 50' of vertical thickness exposed not a single pebble or 

 bowlder is to be seen. The clay is of a grayish-drab color 

 with a slight reddish tinge. 



Bowlders of Catslcill calcareous breccia, of immense size, 

 are very common in the Drift both along the streams and over 

 the uplands south from the east and west divide. Along 

 the valley of Martin's creek they are of frequent occur- 

 rence. Over the uplands of Wayne they are often seen in 

 immense numbers, 3' to 6' in diameter, generally rounded, 

 though always roughened by weathering. 



Drift deposits fill the valleys of the Lackawaxen creek 

 and its tributaries, causing the very gentle fall in the Dye- 

 berry between Honesdale and Tanner's Falls. 



