WAS THEEB AN INTBRGLACIAL PERIOD IN MAINE? 287 



interglacial period ought to rest in observations made in more places than 

 one, and in places where there can be no suspicion of landslips. 



2. I have examined the place since reading- Professor Hitchcock's pub- 

 lications, also after he has kindly written me descriptions. Near the same 

 locality Dr. Wilham Wood and Mr. C. B. Fuller, of the Portland Society 

 of Natural Historj^, have recently exhumed a skeleton of a walrus in sandy 

 clays. I l:|^ve examined several excavations in that vicinity (all that are 

 now open), and can not be sure that I have seen the exposures referred to 

 by Professor Hitchcock. I have found masses of rounded cobbles and 

 bowlderets overlying the fossiliferous marine beds, also small masses of 

 more till-like' appearance. Both Avere in material that had slipped dowii 

 from the hill above; but not to insist on this, let it be assumed that both 

 kinds of deposit can there be found overlying the marine beds in situ. 



If the "upper till" referred to by Professor Hitchcock is composed of 

 the rounded gravel and bowlderets, we have a case here of transportation 

 by water as well as by ice. The great giacial river which reached from 

 the upper Androscoggin Lakes to Portland could transport bowlderets 

 beyond the front of the ice into the sea, especially in the^time of summer 

 floods. It is a possible interpretation that the ice was confronting the sea, 

 and if so it might often happen that matter brought down by glacial rivers 

 would be dropped on marine beds jjreviously laid down. The presence of 

 such water-rounded matter is not of itself a proof of a readvance of the 

 ice over the fossiliferous clays. 



But if this "upper till" was transported not by water, but by ice, we 

 have at Portland substantially the same problem as the supposed one at 

 the Waldoboro moraine overlying the marine clay. The problem is to 

 determine whether here are two presences of the ice such as warrant the 

 correlation of the Maine deposits with those of the Interior. 



3, During' the latest glacial period in the Northwest there were dej30S- 

 ited the great kettle moraine and broad sheets of morainal drift (up to a 

 breadth of several hundred miles), varying in depth up to 400 or 500 feet 

 or more. The amount of till overlying a supposed interglacial clay at 

 Portland, and perhaps at Waldoboro, is inconsiderable compared with the 

 great sheets and moraines of the Northwest. We can not correlate them 

 unless it can be proved that in Maine the ice carried less morainal matter, 

 so that smaller moraines represent a greater relative time of deposition. 



