'i\0 Nftff's OH the Locr/J (rfiolof/i/ of M'udy/fo Ji^chrlolf. 



near its nioiitli. From tlie middlo of the south line of section 28, 

 a low valley stretches to the middle of the north line of section 

 2*^ in the village of So.ith Bend and there connects with 

 the flood plain of the Minnesota river. This valley is closed 

 in on either side by ridges of Shakoj)ee and .Jordan sandstone. 

 There are several ponds in this valley with their longest measure 

 along the line of the valley. Wells sunk in the valley, have found no 

 water and have been dug in black sandy loam for their entire 

 depth. At the time when the 'Blue Earth river flowed along this 

 €0ursvi the Minnesota flowed along the north shore of its flood 

 plain, swept southeast to wliei-e the wagon bridge crosses the Blue 

 Earth river at Mankato, and then turned northeast; thus estab- 

 lishing the same conditions as existed before between the Blue 

 Earth and Le Sueur rivers, and the same result followed, the old 

 channel was forsaken and a new one, across the ridge tangent to 

 the two curves, was taken. In my own thoughts, I have been in 

 the habit of regarding an ice gorge as the occasion for the first 

 break in the channel. Recent observations on the immense amount 

 •of sand carried by the waters of the Le Sueur and Blue Earth, the 

 way in which this sand is heaped up into sand banks, the current 

 changed and the eroding effect of such current on the banks 

 ^'igainst which it im[)inges directl}^, while it is powerless to move 

 the j-and bank, incline me to the view that this heaping up of sand 

 in the channel may have been a cause, if not the cause, for 

 the changes of channel in these rivers. Why the Minnesota and 

 Blue Earth cut through and formed the terrace like knolls, situated 

 one on either side of the Blue Earth at its mouth, and parted 

 them from the Nicollet county bank of the river is to me a puzzle 

 for which I can not offer any satisfactory solution. 



THK GEOLOGIC AGE OF SOME CLAYS FOUND AHOUT MAXKATO. 



At the Kunz (juarry, four miles northeast of Mankato, in the 

 C. St. P. M. & 0. R. R. cuts at West Mankato and South Bend, above 

 the wagon road behind the brewery at the Blue Earth river, in the 

 -<:|uarries at the cement works, at the ''Mound" on the west bank of 

 the Blue Earth river near the mouth and along the banks of the 

 Le Sueur river are found banks of clay, genernlly white in color, 

 filling fissures on the Shakopee limestone and upon which is found 

 "the material of the drift, as yellow clay, boulders of granite and 

 limestone and now and then masses of ferruojinous sand, forraino: 



