358 



THE GLACIAL LAKE AGASSIZ. 



56, it varies from 1,220 to 1,227 feet. From this crest of the southern part 

 of the deha it slopes slowly east aud northeast to 1,080 and 1,09(J feet at 

 its eastern border, in sections 25, 24, and 13, which coincides nearly with 

 the east line of this township 162, range 56. Deep valleys, with frequent 

 tributary ravines, have lieen eroded in it by several small streams. West- 

 ward the delta reaches to the base of the second Pembina Mountain, the 

 belt, a half mile to 1 mile wide, next beyond the crest, only about 5 feet 

 lower, being a very flat, beautiful prairie, which rises slowly, like the crest, 

 from south to north. The elevation of this l)elt in section 18, township 

 161, range 56, is 1,190 to 1,195 feet, and at Mr. Henry Golf's house, in the 

 middle of the east edge of section 36, township 162, range 57, 1,221 feet. 

 Farther west there is an ascent to about 1,240 feet at the base of the "sec- 



)':oo-^~Seconc/ Fembi'na Moi/nfsi'n 



Fig. 15. — Soctiuu across the delta of the Peiubiua River. Horizout:il .scale, 2 miles to an inch. 



ond mountain." Wells on this area penetrate only beds of sand and gravel, 

 easy to dig and needing to be curbed to prevent caving. A large propor- 

 tion, 23i"ol)ably half, of the gravel is Cretaceous shale. Water is obtained 

 at depths varying from 25 to 60 feet. 



The part of the Pembina delta thus far described is divided from its 

 central and higher part, which is crossed by the section of fig. 15, by a 

 depression about a mile wide, through which a portion or the whole of the 

 river flowed duinng much of the time while this delta was being formed. 

 In the southwest corner of section 18, township 162, range 56, this depres- 

 sion is 1,205 feet above the sea, being 20 feet lower than the area on the 

 south. It extends eastward with a slow descent and rises westward to 

 1,215 feet close east of the Little Pembina River, in section 15, township 

 162, range 57. This stream flows through the escarpment of the "second 



