114 Kansas Academy of Science. 



They are composed mostly of gravel and cobblestones. The spit 

 at Blaine is used as a site for fish canneries. The other spits are 

 used as camping-places in the fishing season. 



Delta Deposits. — These cover large areas both at the mouth 

 of the Fraser and the Nooksack-Lummi rivers. The Nooksack 

 delta is quite thick. Logs in it have been found thirty feet be- 

 neath the surface. This delta, where it is not swampy, contains 

 some of the best farms of the region. There are also some fine 

 farming sections in the Fraser delta. 



Estuary Deposits. — These are found in the valleys of the 

 Fraser and Nooksack rivers, above the respective deltas. As has 

 been stated, these regions were at or below sea-level at the close of 

 glacial times. While thus depressed a coarse, ash-gray sand was 

 spread over the Nooksack estuary from a few inches to many feet 

 in thickness. The thickest deposit of this sand is on the west or 

 slack- water shore of the estuary (the glacial sands are finer and are 

 all brown to light yellow in color). While this sand was being de- 

 posited in the slack-water region away from the mouth of the 

 Nooksack river, that river was depositing gravel on the current 

 side. Besides that the waves of the estuary were forming beach 

 gravel by their pounding against the walls of the Sumas mountains 

 on the east and by their tearing down and leaching out the finer 

 material of the glacial deposits of the push-medial moraine to the 

 northwest, the coarser material being left behind as gravel and 

 cobblestones. That these deposits were laid down in sea-water is 

 attested by the fact that they all contain marine shells. Sea-shells 

 were found in them seventy feet above present sea-level. The sites 

 of these estuaries are now occupied, in part, by low prairies ; the 

 Bertrand prairie is situated in the Nooksack estuary, the Langly 

 prairie in the Fraser. 



Lake Deposits. — Deposits of this type are often very thick. 

 They are composed mostly of sand, silt, and peat. 



Swamp Deposits : These cover a great part of the delta and 

 estuary areas and are also found bordering the glacial lakes. The 

 swamps of to-day, however, cover a much less area. The deposits 

 are composed mostly of black muck and peat. When tiled the 

 swamp regions make fine farming lands. 



