598 WILLIAM J. MILLER 



sandy clays and pure clays, while sandy clays are distinctly less 

 conspicuous among the contorted beds. Figure 6 represents a 

 detailed sketch of part of this corrugated zone, a feature of excep- 

 tional interest being the only slightly disturbed layer of fine-grained, 

 sandy clay lying in the midst of the contortions. This contorted 

 zone about 8 inches in thickness may be traced for a number of rods 

 in the walls of the clay pit, but its full extent is unknown. Above 

 it about a foot there is another corrugated zone lying between prac- 



FiG. 5. — Highly contorted zone (8 inches thick) of clay between practically 

 undisturbed beds of clay and sandy clay in the bank of the Connecticut River 2 miles 

 east of Northampton, Massachusetts. 



tically undisturbed beds. Within the clay pit the beds show a very 

 appreciable dip of at least several degrees to the southeast. 



It seems impossible to explain intraformational contorted clays 

 like those just described except as a result of differential movements 

 after the clays overlying the contortions were deposited. An 

 explanation commonly given for such phenomena, but rarely if 

 ever supported by anything hke reasonable proof, is that the con- 

 tortions were caused either by ice thrust, or the bumping or crowding 

 of icebergs on surface layers which were afterward covered by more 

 clays. Some facts opposed to such a hypothesis are: (i) the 

 remarkably uniform thinness of the corrugated zones of such wide 

 extent which could hardly have resulted from ice action upon 

 surface layers, the development of such zones under considerable 



