CHAPTER XXII. 



MAN AND THE GLACIAL PERIOD {contlnueiT). 



The preceding instances all belong, without question, to 

 the later stages of the Tee age in America. Those geologists 

 who speak of two glacial periods would classify the gravels 

 at Trenton, N. J., Madisonville and Loveland, O., Medora, 

 Ind., and Little Falls Minn., as belonging to the later stages 

 of the second Glacial epoch— the deposits at Little Falls 

 being, as Mr. Upham has already stated, somewhat subse- 

 quent to any of the others. We come now to a still more 

 startling discovery, made by Mr. Cresson, near his summer 

 residence, on the Delaware River, at Claymont, Del. For a 

 general idea of the situation the reader is referred to the 

 map of New Jersey in the general chapter upon the glaciated 

 area.* The discovery was made while an extensive excava- 

 tion was in progress connected with the building of the Balti- 

 more and Ohio Railway. It was my privilege, in November 

 1888, to examine the locality in company with Mr. Cresson,. 

 and I here give the results of the observations : 



The point is located about one mile and a half west of 

 the river bank, and about one hundred and fifty feet above 

 tide-water. The ascent from the river at Claymont is by three 

 or four well-marked benches. These probably are not ter- 

 races, in the strict sense of the word, but shelves marking dif- 

 ferent periods of erosion, when the land stood at these sev- 

 eral levels, but now thinly covered with old river deposits. 

 The cut where the discovery was. made is well shown in our 



* See p. 141. 



