112 GLACIAL GEAVELS OP MAINE. 



hummocks grow smaller, and the series ends within about 2 miles. To the 

 ;south of this point lies a low clay plain all the way to the sea in Addison. 

 In this I could find no glacial gravel rising above the clay. The only east- 

 ward or southward connections of the Epping Plains which I have been 

 able to find are certain broad plains which extend through Columbia Falls 

 eastward toward Masons Bay, Jonesboro. In the midst of the Deblois- 

 ' Columbia Plains are several areas of till rising above the gravel plains. 



Near Epping Church, Columbia, is an excavation showing an interest- 

 ing section. On the top is a thin layer of well-rounded, medium-sized 

 gravel. Beneath this is a stratuni 2 to 4 feet thick containing unpol- 

 ished stones and bowlders having the shapes of tillstones. This plain, 

 being below the contour of 230 feet, would project from the west far out 

 into the expanded bay of that time occupying the valley of Pleasant River, 

 and would be much exposed to stranding ice floes. I do not see how in 

 general the scattered and isolated bowlders having till shapes found upon 

 and in the marine clays can have been brought to their present positions 

 except by ice floes or small bergs. But this till-like stratum is so continuous 

 that I see no objection, so far as the mass itself is concerned, to considering 

 it a sheet of till. The till-like mass is found on the eastern end of the 

 high plain, and does not extend far west of Epping Corner. This is where 

 the ice floes would be most liable to run aground, and it is a point in favor 

 of the ice-floe theory. I saw no bowlders distinctly glaciated, but this is 

 not fatal to the theory of a readvance of the ice after the deposition of the 

 plain of gravel. On either theory the surf wotild subsequently beat on top 

 of the plain and wash down some of the highest gravel onto the adjacent 

 till-like mass, though in manj^ places there is no overlying beach gravel. 

 As one goes over much of the plain near Epping the angular or unpolished 

 bowlders make it look so much like a field covered by ordinary till that it 

 needed the testimony of those who have fruitlessly dug wells to a great 

 depth to convince me that the plain is underlain by 100 feet of coarse 

 glacial gravel. A more careful exploration of the whole region is needed 

 in order to decide the question of the origin of the till-like stratum. At 

 present I incline to favor the ice-floe theory. 



Comparing the gravel of the Katahdin osar with the till, also with the 

 ■country rock of the regions through which it passes, we find that both the 

 till and the osar are made up chiefly of fragments of local rocks or of rocks 



