DEPOSITS ON SWIFTCURRENT RIDGE 701 



rods. It gradually increases in elevation from about 5,800 feet above 

 sealevel at the east to 6,000 feet at the west, so that it stands about 1,150 

 to 1,250 feet above Swiftcurrent Creek on the south. From this top 

 steep slopes decline on either hand. At the top of the south slope is an 

 abrupt scarp due to landsliding. This has a height of 200 to 300 feet, 

 and below is an uneven slope marked by swells and sags and numerous 

 small lakelets. This slope resembles morainal topography, but is prob- 

 ably principally due to slumping of the drift over the soft Cretaceous 

 shale. Two hundred feet or more of glacial till is exposed in the clean 

 scarp faces at the top of the slope. This drift is of the same composi- 

 tion and appearance as that on the ridge across the valley to the south 

 excepting that here, in addition to the other ingredients, fragments of 

 Siyeh limestone and amygdaloidal trap rock are found. The latter is 

 present in the mountains at the head of Swiftcurrent Valley. Many of 

 the pebbles and boulders are beautifully striated. Blocks of the tillite 

 conglomerate were seen, but no ledges clearly in place. Part of the 

 diorite boulders are considerably weathered so as to be exfoliating shells 

 half an inch thick, and some of the limestones in the upper part are 

 etched but not removed by solution. The drift on the whole looks fresh 

 and shows but little modification by weathering. 



At the west end of the high tract just described the ridge narrows and 

 the crest is broken by a sag about 1% miles in length. This part is 

 crossed by the boundary between the Blackfeet Indian reservation and 

 Glacier Park. Here the drift capping has been removed and Cretaceous 

 shale is exposed at intervals. Beyond this the crest again rises and a 

 narrow remnant of the old drift remains. This part of the ridge was 

 examined by Mr. Thomas, but not seen by the writer. Mr. Thomas 

 reports a notched flat crest rising from 6,100 to 6,200 feet above the sea, 

 and scarps giving good exposures of 200 feet of glacial drift like that 

 forming the top of the ridge farther east, with ledges of tillite con- 

 glomerate in place. On the surface boulders of diorite and amygdaloidal 

 trap are conspicuous, some being 4 to 6 feet in lengtli. The drift was 

 observed in place to within a few hundred feet of the pre-Cambrian 

 Altyn limestone in the east end of Appekunny Mountain. "West of a 

 notch there is an abrupt rise to a bench at 6,300 feet above the sea. 

 This is cut in solid limestone and extends for a short distance about the 

 north side of the point of the mountain. On this bench no drift was 

 found. The top of the drift stands nearly 1,500 feet above Swiftcurrent 

 Creek on the south and 800 feet above South Fork of Kennedy Creek 

 on the north. From the topographic relations and the presence of the 

 tillite conglomerate, there is little room for doubt that this high level 



