VALLEY OF SALMON RIVER. 353 



that caps the ridge and is only 200 or 300 feet wide and a short fourth of a 

 mile long. It formed in lee of a small peak of volcanic rock that projects 

 about 30 feet above the side of the little peak, and a few glaciated stones 

 are also found on the other two sides of the crag, but none on its top. 

 Perhaps a better name for this arrangement would be "crag and collar." 

 This is about 500 feet above Napius Creek. 



Crag and cap. — About 3 uiiles cast of the last-named locality and 1 mile 

 south of Napius Creek is an oblong-conical hill rising about 800 feet above 

 the creek. The top of the hill is capped by a ridge of glaciated matter and 

 erratics. The local rock is a dark schist entirely unlike the morainal mat- 

 ter. The ridge is hardly one-eighth of a mile long and 250 feet wide, with 

 steep lateral slopes. It contains many granite bowlders from 10 up to 20 

 feet in dianieter. 



I noticed several other moraines capping hills at different elevations. 

 These moraines are separated by large areas that show little or no foreign 

 matter. We have not a sheet of till, like that which covers New England, 

 but local masses here and there. The situations of these high moraines 

 described as crag and collar and crag and cap appear to be similar to the 

 moraines now forming at the nunatakker of the Greenland ice-sheet. They 

 probably formed when the hills rose near or above the surface of the ice. 

 It is doubtful whether this drift was transported subglacially or supergla- 

 cially, or both. The large areas bare of transported matter favor the 

 hypothesis of much of surface transportation ; the intense glaciation of 

 much of the morainal matter favors the subglacial hypothesis. 



GLACIAL GRAVELS. 



One of the most noticeable features of this valley is the large sheet of 

 waterworn gravel, cobbles, and bowlderets, with some bowlders, which once 

 filled the bottom of the main valley and thence extended up the lateral val- 

 leys for several miles. The stream has eroded the old plain to depths of 30 

 to 70 feet, the uneroded portions forming terraces, known to placer miners 

 as bars. As we go back from the stream the gravel slopes upward 100 or 

 more feet per mile. Excavations for placer mining show that under the 

 gravel lies well-glaciated rock in place. The gravel plain is 2 miles wide 

 a short distance west from Leesburg. Mixed with much waterworn matter 

 are some stones bearing glacial scratches. The proportion of this sort of 



MON XXXIV 23 



