BLUE EARTH COUNTY. 43] 



Shakopee limestone.] 



At Garden City the Shakopee limestone is exposed on a small island and in the left bank of 

 the Watomvan river, close below the dam and mill. The area of these exposures is about four rods 

 square, and their hight three to five feet above the water. Professor Winchell records the occur- 

 rence of a species of Euomyhalus in this stone, apparently the same fossil that was described and 

 named Stmparollus Minnesotensis by Owen. This rock has nearly the same aspect as at Shakopee, 

 having frequent cavities, and being sometimes a breccia. It lies in thick beds which are irregu- 

 larly tilted and dip syncliually 10' to 20 ; from both north and south into the river. The probable 

 explanation of this is that this limestone, at first horizontally stratified, has been fractured by the 

 removal of a part of the underlying friable Jordan sandstone, through pre-glacial drainage into a 

 river lower than that of the present time. Another outcrop of this limestone is found a third of a 

 mile northeast from Garden City, on land of the S. M. Folsom estate. It is at the northwest side 

 of the Watonwan river, and is principally covered with drift, being seen at only a few small ex- 

 cavations upon an area fifty feet long and fifteen to thirty feet wide, adjoining the river and grad- 

 ually rising about five feet above it. It has layers one foot or more in thickness, and has been 

 somewhat quarried. 



The valley of the Le Sueur river has an outcrop of this limestone on land of Andrew Algren. 

 in the N. E. J of section 1 1 , Kapidan, being on the southwest side of the Le Sueur about two-thirds 

 of a mile below the mouth of Maple river. The ledge seen here reaches five feet vertically, and is 

 in level beds six inches to one foot or more in thickness. It is about twenty rods from the river 

 and fifteen to twenty feet above it. 



On the Maple river the Shakopee limestone is quarried at many places within a mile above 

 its mouth, and occasional low outcrops of it are found along the next mile, to the south part of the 

 N. W. } of section 24, Ilapidan. At these quarries the stone is a compact, light-buff dolomite, of 

 nearly uniform texture and color, in horizontal layers one to three feet thick, reaching from the 

 level of the river to nights twenty to thirty feet above it. 



On the Big Oobb river this formation outcrops and is slightly quarried three-fourths of a 

 mile and one and one-fourth miles above its mouth. The first of these localities is on land of 

 Matthew Ryan, in the S. E. J of section 18, Decoria, where this stone makes a terrace which ex- 

 tends about a quarter of a mile in the bottom land, being twenty to twenty- five feet above the 

 liver and seventy-five feet below the top of its bluffs and the general surface of the drift. The 

 highest points of the limestone here are fully thirty feet above the river, and have the form of 

 isolated mounds of horizontal strata, which have been spared, while the continuation of the snme 

 beds has been removed, by the agenciesof weathering and erosion. These mounds rise ten to fifteen 

 feet perpendicularly or often with overhanging sides. A similar picturesque weathering of this 

 limestone, forming many such mounds five to ten feet high, was also seen four miles north of 

 Mankato, on land of Joseph Kunz, in the S. E. J of section 19, Lime. At Mr. Ryan's quarries, 

 near the south end of the exposures of rock on his land, its night at the east side of the river is about 

 twenty feet and at the vfest side ten feet, their distance apart being ten or twelve rods. This 

 stone has the same characters as in the quarries of Mankato and Maple river. It lies in beds 

 which are from one to four feet thick, their stratification on the east side of the river being nearly 

 level, but on the west side dipping 5 to 10 ? west. About a half mile farther south, on land of 

 A. W. White, in the N. E. J of section 19, Decoria, the Shakopee limestone is again exposed, 

 forming a vertical cliff which rises from the level of the river to about thirty-five feet above it, in 

 its left (here the northern) bank. It holds this hight for an extent of nbout ten rods, and contin- 

 ues with decreasing hight as much farther westward. At its west extremity this limestone is 

 overlain by Cretaceous beds; but mainly this ledge is covered by till, which reaches seventy-five 

 feet above the river. 



The elevation above the sea of the outcrops of Shakopee limestone on the Watonwan river 

 at Garden City and on the Maple and Big Cobb rivers is 875 to 900 feet, being about fifty feet 

 higher than the top cf this formation in Mankato and Lime, eight to twelve miles farther north. 



Cretaceous beds. The only deposits found in Blue Earth county above 

 the foregoing Lower Magnesian strata and below the drift are beds of clay, 

 sand and sandstone, and rarely gravel, which are believed to have been 



