GLACIATION IN THE CRAZY MOUNTAINS 563 



been broadly opened and straightened by normal erosion, so that ice action has 

 not greatly modified them. 



stri;e an'd depth op cutting 



Striae are found only in the upper parts of the larger canyons, in the region 

 of the hard rocks of the igneous cores and contact zones of the mountains. 

 Elsewhere the rocks have weathered sufficiently to remove or conceal the ice 

 markings. Even in the I'egion where the rocks are hard, slide rock and mo- 

 rainic material mask the glaciated surfaces so that actual striations are not 

 frequently seen. Well developed roches moutonees were, however, studied in 

 Big Timber and Sweetgrass canyons and more distantly observed in other can- 

 yons. The directions of all strife seen agreed with the general trends of the 

 valleys in which they were found. The presence of striae indicates that the 

 original valleys have been deepened by the ice to some extent at least. Out- 

 side the hard rock area the canyons have doubtless been more deeply eroded, 

 and then partly filled with glacial and fluviatile material. The general depth 

 of the filling is not known, since most of the streams have not yet succeeded 

 in cutting through it. In Cottonwood (Pine) canyon, however, about 3 miles 

 below the junction of the north and east forks, the streiim has reached bed- 

 rock through 10 to 15 feet of till, which thins out down stream and grades into 

 water-worn material. 



MORAINES AND WASH DEPOSITS 



Moraines are found in the lower parts of the larger canyons, but are usually 

 not well defined toward their heads. Accumulations of slide rock, which occur 

 almost everywhere, have mingled with and obscured the niorainic materials of 

 the upper valleys. Some moraines occur on the western side of the mountains, 

 on the benches sloping northwestward to the Shields River basin, but the 

 heaviest deposits are those previously mentioned in connection with the an- 

 cient piedmont glaciers on the east side. Small lateral moraines occur in 

 some of the canyons. The best examples were seen at the heads of Sweetgrass 

 and American Fork creeks. In many of the cirques little moraine-like humps of 

 slide rock have accnnmhited about the base of the liack and side slopes, ns if 

 loose pieces of i"OCk had fallen on the surfaces of the snow patches that occiipy 

 the cirques, and had been deposited in irregular heaps when the snow melted 

 away. 



Within the area visited by the party there was very little fluvio-glacial ma- 

 terial. Doubtless most of such debris had been deposited farther down in the 

 valleys. In one place, however, a fine section of stratified sands and clays was 

 found, namely, in the valley of the east fork of Duck (Gage) creek, about 

 5 miles south-southwest of Fairview peak. 



LAKELETS 



Niuuerous lakelets occupy rock basins in the cinjues and higher valleys. 

 They are seldom more than 200 or .300 yards in diameter. Sometimes they 

 occur in strings of three or four. They are mostly found in the canyons of 

 streams that flow eastward and southeastward from the mountains, though a 

 few are found in some of the west-flowing creeks. From the snnunit of Crazy 

 peak one of the members of the party counted 18 of these lakelets, several of 



