436 ASSINNIBOIKE AND SASKATCHEWAN EXPEDITION, 



herbage, and on the mountain an ample supply of timber, 

 consisting chiefly of aspen of large dimensions. The 

 Eiding and Duck Mountains consist of a succession of 

 slopes and terraces on their south-western sides, the 

 ascent being almost imperceptible to the thick impene- 

 trable forest which covers the highest plateau. On Birdstail 

 Creek cretaceous shales identical with those on the Assin- 

 niboine crop out in different places, but organic remains 

 are scarce and indistinct. 



Shell Eiver separates the Duck from the Eiding Moun- 

 tain, and its valley affords a very interesting illustration 

 of river terraces. Between the present bed of the river 

 and the prairie plateau it cuts near the crossing place, it 

 discloses three distinct terraces, visible on both sides of 

 the river, but more distinctly marked on the left bank 

 than on the right. On the prairie banks of Shell Eiver are 

 several gravelly ridges resembling in most particulars the 

 Big Eidge ; the elevation is thirty feet above the level on 

 which they are formed. The length of the slope to the 

 summit varies from 100 to 180 feet ; the course is nearly 

 north and south, or nearly at right angles to the point 

 where they touch the bank of the stream. The ridges 

 die away in the general rise of the prairie as they recede 

 from Shell Eiver. They are thickly covered with 

 boulders. 



Although several landslips have revealed the structure 

 of the banks of Shell Eiver, yet no rock in position was 

 observed. The banks consist, according to Mr. Dickinson, 

 of clay, sand, and gravel mixed with a few boulders. 

 Near the confluence of Shell Eiver, or A-se-sepee as it is 

 termed by the natives, with the Assinniboine, some In- 

 dian graves are placed on the edge of the bank, sad 

 memorials not unfrequently met with in travelling through 

 these beautiful wastes. 



