1875.] ^^1 [Hall. 



by the glaciev after it had receded through the Gap, possibly a lateral 

 moraine. 



Wind Gap. 



From the few evidences observed, I concluded that here, too, the gla- 

 ciers had crossed the Blue Mountain Range. North of the Gap I observed 

 nothing remarkable. South of the Gap are great numbers of boulders of 

 Oneida conglomerate and Medina sandstone. They are strewn along for 

 some distance in a direct line with the Gap, and apparently mark the 

 course of a moving body. 



Not having observed Oriskany sandstone associated with the boulders, 

 I attributed to the fact of it being more easily disintegr^ited. 



Delaware Water Gap. 



The first notice I took of decided glacial action in this vicinity, was 

 about four miles from the mouth of Marshall's Creek, on the road to 

 Craig's Meadow, where there are extensive exposures of the Oriskany 

 sxndstone, undulating and pitching gently to the northward. 



These beds, often quite level, are scored and scratched wherever ex- 

 posed. Often several hundred squai-e feet are laid bare by the road. 



The direction of these grooves is S.280W., showing the direction of the 

 moving mass to be towards the Gap. That the motion was to southward 

 can clearly be seen wherever there are slight rises in the rock, the north- 

 ern side is more deeply grooved, and more polished than immediately 

 south of it. The full weight of the mass being forced against the rise 

 would not act with the same force till it had passed some distance 

 beyond. 



The same fact as remarked in the White Mountains by Agassiz,(?) where 

 the northern slopes of the mountains are scored and grooved to their very 

 summits, but the scratches do not appear till near the base on the South- 

 ern slopes. 



There are evidences of a moraine about one mile north of the mouth of' 

 Marshall's Creek, near the mill-dam. 



In the neighborhood of Craig's Meadows are large deposits of drift, 

 probably glacial. 



West and southwest of the Gap, about two miles, I observed polished 

 and grooved surfaces of the Medina. 



South of the Gap are large deposits of gravel and boulders, evidently 

 glacial debris. 



Between the Gap and Broadhead's Creek I observed some beautifully 

 defined terraces, but was unable to trace them. These facts tend to prove 

 that the Gaps existed before the glacial epoch, and that the present rivers 

 mark, to some extent, the courses of the ice, at any rate, towards the close 

 of that period. 



