418 GLACIAL GEAVELS OF MAINE. 



aro-ument would not be valid if what I then assumed to be subglacial till 

 is really englacial. The scarcity of di'ift bowlders in some parts of eastern 

 Aroostook County also points in the same direction and toward less intense 

 glaciation eastward as well as northward. Recently Mr. E. Chalmers, of the 

 Geological Survey of Canada, has published the opinion that in eastern 

 Quebec the ice flowed northward into the Grulf of St. Lawrence. Obvi- 

 ously it makes a great difference in our views of the ice-sheet that covered 

 Maine whether we regard it as fed from the Hudson Bay region or by a 

 ndvd in the upper St. John Valley that sent out glaciers north, east, and 

 south. The breadth of the zones of accumulation and wastage would be 

 very differently estimated in the two cases. Such a radiate flow from the 

 tipper St. John Valley would naturally occur during the last of the glacial 

 epoch, no matter what may have been the history of the time of maximum 

 glaciation. Until the St. John-St. Lawrence watershed is thoroughly 

 explored from the White Mountains northeastward, I do not feel justified in 

 insisting on a local ndvd in northeastern Maine, at least as anything more 

 than an incident of the decay of the ice-sheet, although my observations 

 in Maine accord well with that hypothesis. 



Concerning the theory that a continuous osar is in all respects the same 

 as one of the systematically discontinuous series in a more advanced stage, 

 it must be admitted that it is somewhat probable, and yet there are reasons 

 for seriously doubting its tenability. It seems to be difficult to correlate 

 the two classes of deposits when there were so great differences in the 

 conditions under which they were deposited. 



1. The discontinuous gravels of the coast were formed in a region that 

 was at one time under the sea. At the marine deltas we have direct p)roof 

 of subglacial rivers flowing into the sea, and the tunnels appear to have 

 been below sea level. Without assuming that the subglacial tunnels were 

 beneath sea level at the time either the discontinuous or the continuous 

 osars were deposited, the fact that the progressive changes of sea level may 

 have caused the pressure of the sea to extend farther and farther back 

 within the tunnels must be allowed its full weight in casting doubt on the 

 question, What would have happened in the coast region of Maine if the 

 sea had not risen on the land? Before we can admit that the continuous 

 ridges are only an advanced stage of the discontinuous series, and that the 



