POSTGLACIAL BIOTA OF THE GREAT LAKES REGION 165 



a. Bed of Lake Agassiz 



Beltrami County, in bed of Rainy River at confluence of Pine River an<jj. 

 at mouth of Beaudette River. 161 



Sphaerium sulcatum (= simile) Planorbis bicarinatus ( = antrosus) 



striatinum? Galba obrussa 



A specimen of the buffalo, Bison americanus ( = bison) was found in the 

 first rapid on Pine River, in a ridge of gravel mixed with clay. 161 In Clay 

 County, 162 at Georgetown, mussel shells are said to have been found in a well 

 10-12 feet below the surface, in clay. It is unfortunate that these organic re- 

 mains were not preserved and identified. In the Glyndon well, 162 strata con- 

 taining organic matter were passed thru, as indicated below: 



Soil 1 foot 



Yellow quicksand 12 feet 



Blue quicksand, with sheets of turf and vegetable deposits V/i ' 



Blue clay and drift wood 2 " 



Blue clay 2^ " 



Upham (page 664) believes that this material was deposited from rivers in 

 their stages of flood, after Lake Agassiz was drained into Hudson Bay. In 

 Becker County, 163 a bed of shell marl occurs in the banks of Buffalo River in 

 Sect. 28, T. 41, R. 41, seven miles south of White Earth Agency, the stream 

 in the valley being 30-40 feet below the surrounding country. The banks 

 twenty rods southeast from the bridge exhibit in section, 



Soil 2 feet 



White shelly marl 1 " 



Alluvial sand and gravel to level of water.. 6 " 



Total 9 feet 



In Wilkin County, 164 in the town of McCauleyville, in the cellars dug in 

 alluvial clay, many large bivalve shells and small gastropods were found 5 

 feet below the surface and 20 feet above Red River. In this vicinity shells like 

 those of sloughs are often noticed in ploughing or digging, to a depth of six feet. 

 Penhallow 165 records Larix churchbridgensis from southern Manitoba, in post- 

 glacial deposits. 



m Grant, Geol. Nat. Hist. Surv. Min., Final Rep., IV, p. 189. 



1M Op. cit., H, pp. 668, 669. 



183 Op. cit., p. 653. 



lu Op. cit., p. 529. 



155 Rep. Can. Geol. Surv., 1890-1891, p. 143 E, 1892. 



