EELATIOJIS OF VALLEY DRIFT AND OTHER DEPOSITS. 479 



might survive iu very broad valleys. In some cases these reticulated ridges 

 may have been deposited in ice channels near the front. 



Obviously the slopes of the land, the breadth of the valleys, the size of 

 the streams, etc., would determine the development of the gravels after 

 passing out of the ice. 



3. In numerous cases there are north-and-south valleys or passes lead- 

 ing southward to low cols of transverse hills. In late glacial time they 

 contained lobes of ice which were practically local glaciers. Hei-e we not 

 seldom find, a short distance north of the top of the col, a short esker and 

 small terminal moraines. In a number of such valleys there is considerable 

 sediment along the northern slope for several miles. The most probable 

 interpretation is that a fringing lake formed, between the ice and the hill in 

 front, and that the glacial streams continued to pour into this during several 

 miles of ice retreat. 



4. Some valleys contain terminal moraines of considerable size. This 

 implies that the ice front remained stationary, or nearly so, for a time. 

 Such moraines are found in the A^alley of the Androscoggin near the 

 line between Maine and New Hampshire, near East New Portland, and 

 elsewhere. 



In such a case we ought to find a very deej) overwash apron near 

 where the ice stood or paused, and it might even form a dam across the 

 valley and inclose a lake. From this point the sediments would become 

 finer in composition down the valley, and might even pass into the marine 

 clays. 



5. Some east-and-west valleys do not contain osar gravels. Near the 

 end of glacial time the waters of these valleys could not escape southward 

 over the hills bounding the valleys on the south, and the ice would be 

 rather stagnant. There is here no direct proof showing the courses by 

 which the local waters escaped. Some of them woiild flow in subglacial 

 channels, some might escape between the ice and the IpU to the south, or 

 superficially or englacially. It has already been remarked that such of the 

 east-and-west valleys as contain no osar gravels, or were simplj^ crossed 

 by them, contain valley drift which is but little waterworn. This points to 

 small local streams, mostly subglacial and transverse to the ice flow. Such 

 directions would often cause the streams to transport sediments into ai-ms 

 of the sea or into distant north-and-south valleys. After the ice front had 



