EDITORIAL. 627 



account for the fact that the trains of gravel that rise on the 

 outer face of the adjacent moraines run down through this 

 narrower deeper valley at low levels, it is necessary to suppose 

 that there was an interruption of glacial action and a period of 

 excavation during which the previously formed 300 feet or more 

 of glacial wash was very largely carried away, and that this means 

 a discontinuity of glacial action and an interglacial interval. The 

 hypothesis is, therefore, -not a contribution to unity but to discon- 

 tinuity. The amount of excavation between the time of the sup- 

 posed first filling of the trench and the partial refilling at the time 

 of the formation of the adjacent terminal moraine was several 

 times greater than all that has taken place since the moraine was 

 formed. It signifies, therefore, a very notable interruption of 

 continuity and a reversal of action. It may be here added that, 

 logically, it also means the abandonment of the "fringe" theory 

 to account for the older drift, for the filling of the valleys for 

 so great distance and to so great depth means more than a 

 trivial stage of advance, and the excavation previous to the 

 formation of the moraine means more than a slight stage of 

 recession. 



Mr. Leverett has examined the Homewood locality since the 

 meeting, and became satisfied that the partial filling of the trench 

 at that point took place contemporaneously with a moraine 

 which crossed the valley only a short distance above (some 

 miles outside the glacial boundary as mapped by Lewis and 

 Wright, and even some distance beyond the striae not long since 

 reported by Dr. Forshay, Mr. Leverett finding striation half a 

 mile farther down the valley). The characteristics of this 

 moraine seem to Mr. Leverett to indicate that it belongs to the 

 group formed during the later incursion. The shelf of rock 

 south of the tributary was not covered by the glacial wash of 

 this stage because the trench lacked about twenty feet of being 

 filled by the wash. Mr. Leverett found other remnants which 

 he regards as parts of the same glacial flood-deposit farther 

 down the Beaver, the surface rapidly descending as is the habit 

 of such moraine-headed terraces near their sources. The facts 



