﻿1861.] 



HECTOR ROCKY MOUNTAINS, ETC. 



407 



syenite, which Mr. Bauerman told me occurs in the Cascade Range. 

 Often in the woods to the south of Fraser River I saw solitary 

 boulders 6 or 8 feet high, resting apparently on the shingle-terraces 

 which here are only 100 to 200 feet above the sea. Certainly at 

 the Fourth Plain, five miles from Fort Vancouver, there are several 

 large blocks, though not of the above size, that do rest on the gravel- 

 terrace which skirts the valley of the Columbia River. On most of 

 the islands in the San Juan Archipelago, and along the coast of 

 Puget Sound, high sections of yellow sand and clay are exposed, 

 forming the sea-shore. The terraces are there further inland. 

 From this drift Mr. Bauerman procured casts of Cardium and 

 ScLvicava. 



As I never observed drift or boulders within the Cascade Range, 

 even in places elevated only 600 to 700 feet above the sea, but as 

 all the superficial deposits in the great trough between that range 

 and the Rocky Mountains are clearly formed from the rearranged 

 materials of the shingle -terraces along with tufas from the Cascade 

 Range, I conclude that the average lowest altitude of the Cascade 

 Range, which is somewhere about 4000 feet above the sea at the 

 present time, exceeded the depression of the continent during the 

 glacial epoch, and presented a barrier to the causes which transported 

 the erratics and scratched the rock-surfaces along the Pacific coast. 

 If the Cascade Range at that time formed a promontory enclosing a 

 gulf like the Gulf of California, it would exactly fulfil these condi- 

 tions. 



TERTIARIES. 



The existence of Tertiary* strata, ascertained to be so by their 

 organic remains, has only been proved at one point west from 

 the Cypres Hills, where Mr. Sullivan obtained Ostrea Veleniana, 

 associated with a Modiola and a few other fossils, which Mr. 

 Etheridge, who has named all the Cretaceous and Tertiary fossils 

 brought home, has been unable to identify. The beds from which 

 these fossils were obtained consisted of friable sandstones with argil- 

 laceous and calcareous concretions, with massive and irregular bedding, 

 and often passing into incoherent pebble-conglomerate. Judging alone 

 from mineralogical resemblance, these beds were recognized over a 

 considerable area, but always forming high grounds in the neighbour- 

 hood of the Missouri Coteau, S.E. from the mouth of Belly River. 



On the Souri River, seven miles north of the boundary-line, in 

 longitude 104°, was observed what is perhaps a portion of the 

 Missouri Tertiary lignite-basin. This locality, which is known to 

 the half-breeds as " La Roche Percee," is well up the eastern slope 

 of the Missouri Coteau, and within a degree of latitude of that river 

 itself, at a point where the existence of the lignite of Tertiary age 

 has been well ascertained. 



The Souri River at this point flows through a valley with steep 

 sides, depressed 165 feet below the surface of the plain, which at this 



* Using the term in its limited signification, as including Eocene, Miocene,, 

 and Pliocene. 



