PLATE LX. 



BECKER COUNTY, 1888. WARREN UPHAM. 



This county is also so covered by drift that no rock outcrop has been discovered 

 within its limits. There is reason for believing that a limestone formation underlies 

 the central, elevated, part of the county. This belief is based on the topography, 

 which shows a marked, rather abrupt uniform tableland or terrace rising from the 

 flat, till-covered portion of the northwestern part of the county, to the altitude of 

 150 or 250 feet above the plains. This elevation crosses Lake Park, Audubon, Detroit, 

 Richwood and White Earth and extends northward in Norman county. To the 

 south it enters Clay county from the east, and passes through Eglund, Parke and 

 Tansem, and through the entire extent of the most western range of townships in 

 Otter Tail county. Throughout most of this distance this elevation is surmounted 

 by a morainic belt, as shown by the maps of volumes I and II. This terrace-like 

 ascent from the Red River valley is a remarkable and conspicuous feature for more 

 than 100 miles. It rises toward the north from the average altitude, in Otter Tail 

 county, of 1,400 feet, to 1,600 feet in White Earth, in Becker county. Owing to the 

 occurrence of numerous fragments of magnesian limestone on the brow of this 

 terrace, sometimes ten or twelve feet in length, west from the White Earth Agency, 

 and at one or two miles south of Audubon, Mr. Upham has suggested that probably an 

 escarpment of such limestone is the primary cause of this terrace. In that case this 

 magnesian limestone, which is probably the Upper Cambrian, may extend for many 

 miles toward the east and north, underlying the region of the sources of the Missis- 

 sippi and of the Red River of the North, and extending with a northwestward dip 

 past the southwestern shores of Lake of the Woods. 



The northwestern part of the county contains a till which was derived largely 

 from the Cretaceous, and such drift was probably brought from the northwest. The 

 rest of the county contains a drift which was derived more from the north, and per- 

 haps from the east by the action of the Lake Superior ice-lobe. 



The name White Earth may have been derived from a shell marl bed found in 

 the banks of the Buffalo river in sec. 28, T. 141-41. 



About five-sixths of the limestone boulders of this county make a white lime, 

 the rest a yellowish lime. This indicates the Upper Silurian as well as Cambrian 

 limestones as the source of these fragments. N. H. w. 



