Uo7) 



respectively the theoretical eastern limits of Cretaceous strata 

 in place and the same as morainal material. 



The same general direction of movement, somewhat further 

 to the east, could have resulted in the transportation of Ter- 

 tiary material from the Marshfield locality to Nantucket, but 

 a change to an easterly movement would have to be assumed 

 if the Tertiary fossils in the moraine at Truro are to be 

 referred to the same general locality for their origin, and 

 such a change is clearly shown by the glacial striae on the 

 rocks of the mainland. The ice evidently spread out like a 

 fan, flowing southward towards the southern coast and east- 

 ward towards the eastern coast, with the farthest marginal 

 extension towards the southeast, in the form of a great lobe, 

 of which the island of Nantucket is the remnant. Nor is it 

 necessary to assume any abrupt change in the direction of 

 movement in order to account for the Tertiary fossils at Truro, 

 as it is a perfectly reasonable assumption that their original 

 home may have been in strata which once extended further 

 north than the locality at Marshfield. 



