472 PROCEEDINGS OF THE ACADEMY OF [1892. 



"At several points in New Jersey, south of all the localities thus 

 far mentioned within the State, there are topographic features which 

 are easy of explanation if ice once extended to the region where 

 they occur, but which seem to be very difficult of explanation on 

 any other hypothesis. The features here referred to characterize 

 the region from Washington, Middlesex county, southwest to Fresh 

 Ponds and beyond, and also the region east of Trenton, from White 

 Horse to Hamilton Square. The topography in these regions is 

 very much like that of a subdued terminal moraine. 



"The determination of the southern limit of ice action duringthe 

 earlier glaciation is likely to be a matter of some difficulty. In its 

 southern extension the ice reached the region of the ' yellow-gravel ' 

 formation." (An. Rep. of State Geologist for the year 1891, pp. 106, 

 107.) 



It is fair to say that Professor Salisbury informs me that he does 

 not now think the ice of " the first glacial period extended farther 

 south than High Bridge and Pattenburg," and would direct special 

 attention to the paragraph quoted, in which he speaks of the possibility 

 of transportation of glacial material by water. But as we have to 

 deal with the report as it stands, it is necessary to call attention to 

 its natural interpretation as it falls into the hands of the ordinary 

 reader, in order to correct the errors into which he would be unwit- 

 tingly led. Such a reader must be informed that when Professor 

 Salisbury speaks of extra-morainic drift extending to the "yellow- 

 gravel" (in quotation marks), he does not mean the yellow gravel 

 as it is marked upon the latest map of the New Jersey Survey, but 

 some yellow gravel which he has discovered a considerable distance 

 farther north. In his paper before the Geological Society, however, 

 he uses language which cannot so easily be explained, saying that 

 boulder clay similar to that at High Bridge and Pattenburg, and 

 whose existence must be explained in the same way, is found south 

 of Pattenburg to a distance fully twenty miles south of the moraine. 

 In the same paper he also speaks of a locality "fifteen miles south- 

 west of New Brunswick," where phenomena are exhibited which 

 present evidences of direct glacial action. 



In the light of my investigations this summer, I think I am able 

 to detect the cause of the conflicting statements of facts by these 

 eminent observers, and to eliminate some very serious errors of inter- 

 pretation which one or other of them has brought into the dis- 

 cussion. 



As I had surmised, and repeatedly urged in publications upon the 

 subject, the cause of the error is to be traced to the undue 



