354 GLACIAL GRAVELS OP MAINE. 



stones increases as we go back from the main creek. Some of these enlarge- 

 ments of the gravel plain may have been deposited in glacial lakes caused 

 by some of the lateral glaciers flowing across the main valley and damming 

 it. I nowhere found, however, anything that resembles the reticulated 

 kames, though there are here, as in numerous places in the Arkansas Val- 

 ley, low swells or ridges obliquely transverse to the course of the glaciers 

 showing one slope of the cross section shorter and steeper than the other. 

 In all cases the distal slope is the steeper. A large amount of water-rounded 

 matter is found in the valleys below the -region visited. 



An ice-sheet covered the bottom of the valley of Napius Creek and 

 rose above the hills near the river. Higher in the mountains the hills sepa- 

 rating the lateral valleys probably rose above the snow; they certainly rose 

 far above the confluent glacier of the main valley. This ice-sheet formed 

 "nunatak" moraines at various points, but no continuous sheet of till. The 

 ]Droportion of water-rolled as compared with morainal matter is very large. 

 This seems to indicate that this gravel plain was formed in front of the ice 

 during the final melting. The much-rolled matter was poured out by the 

 subglacial streams in front of the ice, and the morainal matter that was on 

 or in the ice fell into the water at the ice front, and thus received too little 

 waterwear to eff"ace the glacial scratches. The gravels poured out during 

 the time of maximum depth of ice are beyond the field explored. 



GENERAL SUMMARY OF THE ROCKY MOUNTAIN REGION. 



The above-recorded observations cover nearly 10 degrees of latitude, 

 though most of them were made in the State of Colorado. 



Several characteristics of the glaciation of the mountain region deserve 

 attention. 



1. All writers are agreed that the mountain glaciers were confined to 

 single drainage basins. We find the nearest approach to ice-sheets in the 

 larger valleys, where the tributaries united to form glaciers that rose above 

 the low hills and ridges nearest the main ^^alleys. 



2. In general the moraines formed at the ends or margins of the 

 glaciers, not subg'lacially, with a residue of cases where the interpretation 

 is doubtful. 



