SOME OBSERVATIONS ON THE CRUSHING EFFECTS OF 



THE GLACIAL ICE SHEET. 



W. G. Tight. 



It has been our privilege to devote considerable time of late to 

 the study of the drift deposits of Licking county, including also a 

 study of the effects of the continental glacier in modifying the topog- 

 raphy. This region offers a very interesting field for work, as it is 

 located just on the limiting line marking the probable advance of the 

 ice cap. Part of the county being beyond the margin of the ice, and 

 part evidently effected by it. 



While the work is intensely interesting, it is at the same time ex- 

 ceedingly difficult, due to' the subsequent action of the waters of the 

 Champlain and Terrace epochs, thus working over and destroying 

 the glacial deposits, and also on account of the character of the rocks 

 acted upon, which are of a soft character and easily affected by disin- 

 tegrating forces, so that the direct action of the ice, such as glaciation 

 and scoring, is entirely lost. A more extended account of the results 

 of the work done on this subject will appear in some subsequent vol- 

 ume of the Bulletin. At the present writing we desire to call atten- 

 tion to a few observations made at different points in some of the 

 numerous quarries of the county on the character of the disintegra- 

 tion, and we offer them at this time, with the suggestions which they 

 have aroused in our mind, not as representing any finished work, but 

 more to direct attention to the subject and elicit any criticisms and 

 suggestions which may be offered, and to learn whether anything has 

 been. done in this direction, and if so, where the desired literature 

 concerning it may be obtained. Any information on this subject will 

 be thankfully received. Our attention was first directed in this line 

 while, on a little geological excursion with our class. We were struck 

 with the peculiar fractured appearance of the waste or surface rock 

 above the solid stone employed by the quarrymen. The first quarry 

 studied is located a mile north of Newark. Plate A is from a photo- 

 graph showing about half of the quarry, which is located near the 

 top of a high hill about a hundred feet above the creek bed. The 



