460 p. M. FOSHAY AND K. R. HICE — GLACIAL GROOVES. 



from the other side of the river), having its escarpment mostly concealed by 

 the Pleistocene terrace deposit ; while the grooves and striae described below 

 show that the ice extended at least two miles below Chewton, provided laud 

 ice is the only agent capable of forming such grooves in solid rock. 



At the mouth of the Connoquenessing, where is situated a summer resort 

 and picnic grounds (Rock Point), the base-level plain of the Beaver is mostly 

 on the western side of the river, and continues so for several miles in both direc- 

 tions. Toward the north the plain bears upon its surface a large L-shaped 

 kame, a mile in length, which reaches down to a point about one-half mile 

 above Rock Point. This kame is composed of stratified gravel and sand, 

 and has a huramocky and irregular outline. Several kettle-holes are to be 

 seen upon its surface. The direction of the long arm of the kame is uorth- 

 and-south, or parallel to the valley of the base-level plain here, while the 

 short arm lies nearly at right angles to the long one and runs eastward from 

 it, but does not reach to the bluffs of the rock gorge. The kame rises to a 

 height of 25 to 40 feet above the base-level plain, and is from 100 to 300 

 yards in width. It overlies the clayey deposit of the subjacent plain, as 

 proved by excavations into the gravel which reached the clay below, a thick- 

 ness of 11 feet of the latter being here noted. 



On the base-level plain of the Connoquenessing, which is half a mile wide 

 and typically developed for about four miles up that stream and half a mile 

 back from Rock Point, there is another kame about 200 yards in length and 

 40 feet in greatest height. On its surface it bears a typical kettle-hole, and 

 also another partly formed. The direction of this kame is approximately 

 north-and-south, or at right angles to the Connoquenessing valley at this 

 point. The Ell wood Short Line railroad cuts through the highest part of 

 the kame, and the exposed section shows stratified sand and gravel with 

 numerous bowlders up to one foot in diameter. 



On the western side of the Beaver, just opposite the mouth of the Conno- 

 quenessing valley, but more than half a mile back from the rock gorge, there 

 are two smaller kame-like deposits of gravel which abut against the western 

 bounding hill of the base-level plain ; also at Clinton, further southward, 

 there is another good-sized kame-like deposit. All these lie on the base- 

 level plane. 



Potholes. — About half a mile above Rock Point, on the western bluff* of 

 the rock gorge of the Beaver, there are three quarries in the Homewood 

 sandstone, the top member of the Conglomerate series (XII), which stratum 

 here forms the rock floor of the base-level plain. In one (the most north- 

 erly) of these quarries the writers discovered a group of phenomena, which, 

 from their position with reference to the glaciated region as generally de- 

 lineated, are unique in the history of glacial geology. The quarries are 

 worked by stripping off the gravel and clay from the surface of the rock, the 



