552 PKE-WISCONSIN GLACIAL DRIFT IN MONTANA 



Partial Section of interglacial Beds at Lethbridge, Alberta 



Sand, top not exposed. Inches 



Soft, brownish vegetal material to ^ 



Sand 4 



Brownish vegetal material in thin layers 2 



Sand to 3 



Black lignitic material, partly glistening coal % to 1 



Sand, bottom not exposed. 



The beds at this point were much contorted, either as the result of 

 slumping or possibly from having been overridden by the later ice-sheet, 

 so that it could not be determined that the vegetal material had actually 

 grown where deposited. At one point, however, fine rootlike fibers were 

 noted extending downward from one of the vegetal layers into the sand 

 below. This vegetal material probably corresponds to the peaty or lig- 

 nitic material observed by Dawson at this horizon several miles farther 

 down the valley, 10 and represents one of the several phases of interglacial 

 deposition in this region. 



The upper till (D) is of looser texture and a higher percentage of the 

 included pebbles are of Laurentian crystallines than in the lower till (B), 

 although even here a considerable proportion of them are from the moun- 

 tains. 



About 40 rods below the confluence of Willow Creek and Oldman 

 River, a few miles northeast of Macleod, the following section was ob- 

 served : 



Pleistocene Deposits on Oldman River near Macleod, Alberta 



Feet 



D. Gray, sandy, unstratified loam 3 to 



C. Buff to gray, loose till (Wisconsin ?) containing pebbles from the 

 Rocky Mountains and a smaller percentage of Laurentian crys- 

 tallines 15 to 20 



B. Dark, fine, laminated silt (interglacial ?) a few inches 



A. Very dense, hard, gray till (pre- Wisconsin ?) containing pebbles 

 from the Rocky Mountains and a somewhat smaller percentage 

 of crystalline pebbles than in (C) ; overlies the eroded surface 

 of the Willow Creek formation (Cretaceous or Tertiary) and 

 fills two coulees eroded therein 20 to 30 



It is thought that the deposits A and B in this section may. correspond 

 respectively to the deposits B and C in the sections at Lethbridge. 



In none of the sections examined in this locality was the "Saskatche- 

 wan" gravel present, and in none other than the above was any evidence 



10 Geological Survey of Canada, 1882-1884, p. 144c. 



