186 T. C. Ghamberlin — Diversity of the Glacial Period. 



geologists of New Jersey and Pennsylvania, the terminal mo- 

 raine which crosses the river at Belvidere, and which may be 

 spoken of conveniently as the Belvidere moraine, was repre- 

 sented* as the boundary of the glacial drift. This was not 

 rigidly affirmed by the geologists of New Jersey, and from per- 

 sonal statements made to me by Professor Cook at the Paris 

 International Geological Congress in 1878, soon after the 

 appearance of his report on that region, and from recent state- 

 ments of Professor Smock, it appears that a knowledge of some 

 drift outside of the Belvidere moraine was possessed by them, 

 and tha.t the moraine was regarded as representing only the 

 approximate border. Professors Lewis and Wright insisted 

 much more rigidly upon the limital character of the moraine ;* 

 and Professor Lewis published a paper subsequent to his final 

 report on the terminal moraine, in which he attempted to show 

 that all the supposed drift outside of the moraine in Pennsyl- 

 vania except obvious valley wash was illusive. f In recent 

 years several geologists, notably Professor Salisbury, have 

 observed drift on the uplands, extending to a distance of at 

 least 25 miles south of the moraine. Rare occurrences of gla- 

 ciated bowlders have been found fully 60 miles south of the 

 moraine. Professor Salisbury refers a portion of this extra- 

 morainic drift extending in places at least 12 miles beyond the 

 moraine, to direct glacial action at a time much antecedent to 

 the formation of the Belvidere moraine. Respecting other 

 and generally more distant deposits he has reserved opinion. 



It is fair to those geologists who in an early day overlooked 

 this outer drift, or failed to see its full meaning, to note that 

 in its character and expression it is markedly different from 

 the drift of the moraine and from that within it, and that this 

 is ample excuse for the oversight at that stage of work. But 

 even then it did not escape Professor Smock, although we are 

 not aware that he has anywhere published statements concern- 

 ing it. The oversight is less pardonable if the truth be, as 

 insisted by Professor Wright, that this outer drift is of the 

 same age and kind as that of the terminal moraine. 



Notwithstanding his own oversight, Professor Wright insists 

 that those who saw at once the essential facts upon their first 

 visits failed to see what ordinary competency required. In 

 particular, he asserts that Professor Salisbury is in error in 

 referring to a glacial origin the deposits at High Bridge and 

 Patten burg, which lie about 12 miles distant from the nearest 

 point of the moraine. He claims to be able to demonstrate 

 this. One essential part of his demonstration is the assertion 



* Second Geol. Sur. Penn., Rep. Z, p. 45. 



\ On supposed Glaciation in Pennsylvania South of the Terminal Moraine. This 

 Journal, Oct. 1884, pp. 276-285. 



