BLUE EARTH COUNTY. 437 



Cretaceous beds.) 



i 



resemble the beds described in Garden City. At Columbus Ballard's quarry, on the west side of 

 the river near its mouth, in the N. E. J of the 8. W. i of section 12, Kapidan, the west part of 

 the ledge of Shakopee limestone which is worked, is overlain by twenty feet of Cretaceous clays, 

 mostly whitish, in some parts irony, and rarely reddish. Here the limestone has a bight of only 

 ten feet, but it rises twenty feet above the river a hundred feet farther east. Along the last two 

 miles of this river, in the northeast part of Eapidan township, Prof. Winchell describes* "a fri- 

 able, white sandstone. .... underlain by about two feet of a greenish blue clay, and as- 

 sociated with concretionary and irregular sheets of brown hsematite. In the banks of the Maple, 

 where the Shakopee limestone is exposed and somewhat quarried, there are occasional missing 

 places in the beds of that formation. If by the action of the river the section is kept clear, so as 

 to remove th<- drift, this bed of clay can be seen lying with distorted and dishing strata in these 

 intervals. The strata are sometimes not preserved, but the masses appear as if thrust into the 

 excavation in the Shakopee limestone, and are very sandy. In other cases the clay seems to have 

 been shaped in layers conformable to the surface of the limestone, but unconformable with its 

 bedding. At one place the following section can be made out: 



1. Alluvium 15 feet. 



2. Irony crag and impure iron ore 2 feet. 



3. Greenish bedded clay 2 feet. 



4. Strata of Shakopee limestone, more or less stained and encrusted with iron 4 feet. 

 "These parts are arranged, relatively to each other, as shown in Fig. 26. 



Allurium iSf'r 



FIG. 26. SECTION IN THE BANK OF MAPLE EIVEB, KAPIDAN. 



"The white sand . . . is in some way associated with the iron ore. It seems 

 to lie in patches, sometimes just below the iron, and in other places where the iron is wanting. 

 It seems to lie above the clay or shale. ... At other places, a little above the 

 point of the foregoing section, the iron and sand are found irregularly mingled, the iron occur- 

 ring in the form of concretionary sheets, at least in sheets that enclose cavities. As much as four 

 feet of this sand can here be made out, but the clay layer cannot be seen. 



"At a point a few rods farther up, the white sand can be seen in a bluff on the left bank of 

 the river (probably on sec. 13), rising 40 or 50 feet, its exact upward limit being hid by the drift. 

 At the bottom of this bluff the Shakopee limestone is exposed in the form of a rounded water- 

 worn buttress, rising in a solid mass about twelve feet above the river. About this bare rock, 

 which exposes not more than a square rod of surface, or 200 square feet, are fallen pieces of the 

 iron ore mentioned. The rock itself seems coated with thin layers of the irony stone, which yet 

 appear calcareous. No clay or shale, the equivalent of No. 3, of the last section, can be seen. 

 Overlying this iron and mingled with it, is a deposit of white sand, rising, as already stated, 

 about fifty feet. This sand is so incoherent that one cannot ascend it. It slides like drift sand, 

 yet is perfectly homogeneous as sand, without any resemblence to any drift sand. It is purely 

 white. It is mainly massive; yet irregular lines of sedimentation can be seen in it. Also vari- 

 ously arranged in it are little, thin deposits of shale which probably were green till faded and 

 oxydized. These are sometimes an inch thick, but usually not more than one-fourth of an inch. 

 They are in detached, lenticular patches, and not now plastic, but soapy. No fossils can be seen. 

 It seems to lie unconformably on the Shakopee limestone, separated only by a thin bed of greenish 

 blue shale. . . . At a point a little further along, this sand is more persistent, and 

 shows horizontal bedding, by reason of the manner of its falling down from the bluff. Beds, 3- 

 8 inches." 



At the quarries of Shakopee limestone on the Big Cobb river in sections 18 and 19, Decoria, 

 about one and a half miles east from the last, are other Cretaceous beds. In two hollows of this 



*Scond annual report, p. 132. 



