554 THE GLACIAL LAKE AGASSIZ. 



P. Heidei", northwest quarter of section 3-i: Well, 43 feet; water rises 4 feet 

 above the surface. 



Al'ron. — Albert Lntti, northeast quarter of section 34: Artesian well, 36 feet 

 deep ; in till, to gravel and sand at the bottom ; water of good quality rises 4 feet 

 above the surface. Another flowing well in the southeast quarter of this section is 

 only 34 feet deep. 



McCauleyville. — The two following wells are in the village, about 25 feet above 

 the low-water stage of the Eed Eiver, ^vhose alluvium is thus known to reach some 20 

 feet below that level. 



James Nolan: Well, 33J feet deep; soil, 2i feet; brownish yellow alluvial clay, 

 26 feet; dark quicksand, 4 feet; gravel containing shells, like the bottom of a lake, 

 with water, 1 foot and continuing lower. 



In Cyril Boutiette's well, alluvial clay extended to the depth of 45 feet, where 

 was found a layer of abundant remains of rushes and sedges, some of them having 

 their flowering and fruiting panicles and spikes distinctly preserved. 



Mitchell. — C. R. Gleason, northeast quarter of section 28: Well, 27 feet; soil, 2; 

 yellowish gray till, 6 ; gray saiul, J inch ; much harder dark bluish till, IS feet, con- 

 taining plentiful rock fragments up to 6 inches in diameter; underlain by sandy black 

 mud, in which were many small gasteropod shells. This doubtless interglacial fossil- 

 iferous layer, and an interglacial forest bed found under 12 feet of till at Barnesville, 

 in Clay County, both within the area that was covered by Lake Agassiz, show that 

 there was a sufficiently long warm ei^och in the midst of the great Ice age to cause 

 the ice-sheet to retreat northward beyond Barnesville. 



The recession of the ice seems referable, as indicated on page 280, to the Aftonian 

 stage of the Glacial period, between the Kansan and lowan stages of ice accumula- 

 tion. The upper part of the great channel occupied by Lakes Traverse and Big 

 Stone and the Minnesota Eiver was probably eroded by southward outflow from the 

 Red Eiver Valley at that time to a depth somewhat below the level of the upper or 

 Herman beach of Lake Agassiz, and was not subsequently filled with drift when the 

 ice-sheet again covered the land far southward to its lowan liuuts. This interglacial 

 erosion may have reached below the levels of the fossiliferous layers in the wells of 

 Mitchell and Barnesville, allowing these parts of the Red Eiver Valley to have a 

 land surface, while its deeper central part held a lake; or, more probably, as I think, 

 the valley may then have sloped southward, on account of difl'erential northward 

 elevation of the region, so that no lake would be formed during the Aftonian glacial 

 recession in this basin.' 



Atherton. — In the southwest quarter of section 9, a well 37 feet deep has water 

 which rises 3 feet above the surface. 



' Am. Geologist, Vol. XV, pp. 279-282, May, 1895. 



