THE PRE-WISCONSIN DRIFT OF NORTH DAKOTA 



525 



Fig. 4. — Pre-Wisconsin drift resting on Fort 

 Union sandstone, valley of Clear Creek, a tributary 

 of Tobacco Garden Creek, northeastern McKenzie 

 County. 



region and the glacier also caused important drainage changes. 



The best exposures are 



found on Sand Creek, 



a short tributary of the 



Missouri River several 



miles east of Tobacco 



Garden Creek, on 



Tobacco Garden Creek, 



and on Clear Creek, a 



tributary of the latter. 

 Near the mouth of 



Tobacco Garden Creek 



appears 58 feet of till 



in a cut bank. It is 



yellowish gray or drab 



in color, contains many 



small bowlders, and 



rests on Fort Union beds (Fig. 2) . Not far from here is seen 18 feet 



of bowlder clay over- 

 lying 15 feet of well- 

 stratified sand and 

 gravel (Fig. 3). 



The valley of Clear 

 Creek was partly filled 

 with drift and there are 

 many good outcrops of 

 bowlder clay in the fre- 

 quent cut banks along 

 the stream where from 

 30 to 40 feet and over of 

 till is exposed (Fig. 4). 

 The greatest thickness 

 found along this creek 

 was in Sec. 36, T. 1 52 N., 

 R. 97 W., where in a 



high bluff 100 feet of dark gray till overlies 100 feet of soft Fort 



Union sandstone. This outcrop lies within the morainic area to 



Fig. 5. — Pre-Wisconsin drift exposed on the 

 tributary of Sand Creek, northeastern McKenzie 

 County. 



