442 OSCAR H. HERSHEY 



opposite is the lower end of the most important remnant of this 

 old channel, that opened as Cooper's mine, discussed in the 

 paper before cited. It is preserved for several hundred yards, 

 the river occupying a rock canyon on the south of it. At the 

 lower end the deep narrow channel has its floor about 40 feet 

 above the river. On the borders of the deep channel are flattish, 

 water-worn rock benches which probably represent Channel B. 

 Thin remnants of the ordinary river deposit occur in the bottom 

 of the deep channel. The pebbles are well rounded and the 

 granite bowlders comparatively small. Over this occurs 40 to 50 

 feet of a stratified deposit partly of subangular local debris, but 

 abounding in granite bowlders, many of large size. This is not 

 the regular river deposit, thins rapidly down stream, becomes 

 very bulky from here up, and I consider it the combined Crosby 

 Creek alluvium and the overwash gravel and bowlders of a glacier 

 which terminated over a mile up the river. Over it is the strati- 

 fied angular local debris of the Crosby Creek torrent fan, extending 

 to the brow of the hill, nearly 300 feet above the river. Granite 

 bowlders derived from up the river are sparingly scattered 

 through it. 



A ditch in the slope of the mountain just above the inner edge 

 of this alluvial fan, exposes a small area (possibly twenty yards 

 in diameter) of rotten granite bowlders and local debris embed- 

 ded in a sandy clay. It seems to pass down under the edge of 

 the torrent fan and is certainly older. It seems to represent 

 Channel A, having the proper height (350 feet above the river), 

 the aged appearance and the apparent glacial characteristics. 

 On the same line west, but in Crosby Gulch, a large rotten granite 

 boulder is buried under the stratified alluvium of the Crosby 

 Creek fan. 



NEAR AND IN THE GLACIAL AREA PROPER. 



At the upper end of Cooper's mine a depression crossing a 

 rock point seems to represent the deep channel naturally mined 

 off by the river. Its floor is 45 feet above the stream. Directly 

 opposite the present river but in line with the old channel below, 

 the bowlder bed which is so characteristic in Cooper's mine 

 passes into the bank, has been mined somewhat and the rock 



