474 THE GEOLOGY OF MINNESOTA 



f Topography 



The general slope of Martin county sinks slight!}' toward the east, 

 giving direction to its streams. To the traveler this descent is imper- 

 ceptible, and it appears as a vast, moderately undulating, but approxi- 

 mately level prairie. Erosion by the present creeks of this county has 

 depressed them from ten to thirty or forty feet below the average hight of 

 the land on each side, forming along considerable portions of their course 

 distinct valleys, with irregularly sloping, narrow bottomlands, bordered 

 by low but steep bluffs. In Watonwan county the South fork of the 

 Watonwan river lies in a valley which it has cut forty feet below the gen- 

 eral level along all its course from Mountain Lake to Madelia; and the 

 North fork and its tributaries have similarly channeled their part of the 

 drift-sheet. Below the junction of these branches the Watonwan valley 

 increases to fifty or sixty feet in depth before leaving the county at the 

 southeast corner of Madelia. The only place at which these valleys have 

 cut through the drift is in Martin county, on Elm creek in section 6, Rut- 

 land, where the bed-rock, probably sandstone, is found at a slight depth 

 below the surface. 



Adrian, the most northwest township of Watonwan county, has the 

 only outcrop of the bed-rock in these counties, this being the eastern 

 extremity of a prominent ridge of the red Potsdam quartzyte. It is seen 

 at the surface in the N. W. J of section 29. and gives to this and the con- 

 tiguous sections 30 and 19 an elevation fifty to one hundred feet above the 

 rest of this township; but this ridge here, and through its whole extent of 

 nearly twenty-five miles westward, where it rises much higher, is mainly 

 covered by a smooth sheet of till. 



Elevations, St. Paul & Sioux City division, Chicago, St. Paul, Minneapolis & Omaha railway. 

 Copied from profiles in the office of T. P. Gere, superintendent, St. Paul. 



Miles from Feetabov* 

 bit, Paul. the sea. 



Madelia 109.0 1021 



Watonwan river, water 1 10.5 979 



Lincoln 116.4 1042 



Saint James 121.6 1073 



Butterfleld 130.1 1184 



Elevations, Southern Minnesota division, Chicago, Milwaukee & St. Paul railway. 

 From George B. AVoodworth. assistant engineer. La Crosse. 



Miles from Feet above 

 La Crosse. the sea . 



Winnebago City (Faribault county) 166.3 1096 



Fairmont 183.0 1176 



Sherburne 197.5 1273 



Junction of branch to Jackson depot (Jackson county) 209.1 1446 



