524 THE ICE AGE IN NORTH AMERICA. 



lobe of the ice-sheet, forming for a time a land surface which 

 bore timber, was subsequently overspread by an ice-lobe 

 whose current was from the northwest to the southeast and 

 east. The overlying yellowish gray till, spread as a continu- 

 ous and nearly uniform bed only ten to twenty feet thick 

 and forming a nearly level expanse of so much extent, at 

 least 5 miles in diameter, has plentiful limestone fragments 

 from the northwest, being thus in remarkable contrast with 

 the red till deposits lying beneath the gray till in that region, 

 which came from the northeast and therefore has no lime- 

 stone. A well on this area encountering peat and decaying 

 fragments of wood in a water-deposited clay beneath the 

 gray till and at the top of the older underlying modified drift 

 gravel and sand, testifies that this was a land surface with 

 peat and forest trees, previous to the very latest glaciation 

 which brought the yellowish gray till.* 



4. On the southern part of the area of the Glacial Lake 

 Agassiz, at Barnes ville in Clay county, about 190 miles 

 northwest of the Twin Cities (St. Paul and Minneapolis), 

 a well penetrates twelve feet of till, and next beneath, in the 

 bottom of the well, went one foot into quicksand, "contain- 

 ing several branches and trunks of trees, thought to be tam- 

 arack, up to eight inches in diameter, lying across the well, 

 which, together with the inflow of water, prevented farther 

 digging.' ' This well is on the till area of the village of Barnes- 

 ville, about eighty feet below the highest beach of Lake 

 Agassiz, which passes from south to north about three miles 

 east of this village. At the time of my survey of that region 

 and when this volume was published, in 1888, I considered 

 the occurrence of this interglacial bed within the area of the 

 glacial lake as good evidence that the ice-sheet in that inter- 

 glacial stage was melted back at least so far as to give out- 

 flow into Hudson Bay from the Red River Valley, draining off 

 the interglacial forerunner of Lake Agassiz. Subsequent 

 studies and general reasoning lead me, however, now to hold 



* See above p. 184. 



