364 G. F. Wright— Unity of the Glacial Epoch. 



The extensive oxidation spoken of by Professor Salisbury 

 in the quotation made from his recent reports on the glacial 

 deposits of New Jersey, is clearly of preglacial origin. In 

 company with Professor A. A. Wright (a very competent 

 geologist and mineralogist who is familiar with the region de- 

 scribed by Professor Salisbury) I have, during the past sum- 

 mer, gone over the Held pretty thoroughly so as to complete 

 work which the late Professor Lewis and I had contemplated 

 before his death. The area is that occupied by the southern 

 part of Morris county and the northern part of Hunterdon 

 county, New Jersey, and Northampton county, Pennsylvania. 

 These counties border the Delaware River below the terminal 

 moraine as delineated by the New Jersey geologists in 1878 

 and by Professor Lewis and myself in 1880 and 1881. Until 

 recently this moraine has stood as the southern boundary of 

 the glaciated region, and has been regarded as a place where 

 there was no fringe and where the glacial moraine of what was 

 called the '"second glacial epoch" coincided with that of the 

 first. It is fair to say, however, that this part of our work 

 was done by Professor Lewis and myself at the outset of our 

 attempts to trace the glacial boundary and that we then shared 

 with others the supposition that the boundary was everywhere 

 marked by a distinct terminal moraine. 



But in the progress of our work we had our attention called 

 more and more to an attenuated border which we called the 

 "fringe" and which I have attended to almost exclusively in 

 my later explorations of the boundary in the Mississippi Val- 

 ley. In commenting upon this fringe Professor Lewis (see 2d 

 Penn. Geol. Surv. Pep., vol. Z, p. 201) remarks that traces of 

 this il fringe " may be looked for in Pennsylvania and New 

 Jersey, and that the impression had grown upon him " that 

 this fringe is destined to play an important part in glacial 

 geology." Professor Lewis's early death prevented his follow- 

 ing out the clues already then in mind, and I have been unable 

 until the present season to examine the region with sufficient 

 care to enable me confidently to say anything about it. Never- 

 theless, in view of what Mr. McGee has been writing about the 

 Columbia deposits I ventured three "years ago to utter a warn- 

 ing, and to suggest that he might be drawing some unwarranted 

 conclusions from the facts he was presenting, in view of the 

 probability that some of his facts belonged to the fringe which 

 Professor Lewis and I had overlooked in that region. (See Ice 

 Age in N. A., p. 135.) I am now able to demonstrate that 

 both Mr. McGee and Professor Salisbury have been led astray 

 in their recent publications by their failure to notice some of 

 the characteristics of the " fringe " in the Delaware valley. 



