114 



ELIOr BLACKW ELDER 



succession to the east, and raising on the west a lofty wall of Archean 

 gneiss. The exposed scarp along this fault is now more than 7,000 

 feet high (see Figs. 16 and 27) and the total stratigraphic throw 

 can J^ardly be less than twice that amount.^ 



This deformation evidently took place later than the deposition 

 of the conformable Eocene and Oligocene strata. If disturbances 



rf«S»^"''' 



Crcf'<»*^<>(/£ " -flfflll««>i„<-»^!*i. '»^ - .' ua-mmm.^ 



E&cen^ 



Fig. 9 



of this kind had occurred within that depositional interval, they 

 would have caused important unconformities and changes in 

 sedimentation, which are not in evidence. They must also have 

 taken place long before the deposition of the older glacial drift, 

 for the moraines have not been disturbed and on the contrary lie 

 across fault traces along which the scarps have long since dis- 

 appeared. As will be shown later, allowance must also be made 



' For a discussion of the question whether this is a recent fault scarp or an old 

 "fault-line scarp" (W. M. Davis, Bull. Geo!. Soc. Am., XXIV [1913], 187-216) 

 see below. 



