LE SUEUR COUNTY. 630 



Cretaceous clay.] 



Four to five and a half miles farther north is the rock-terrace on which Ottawa is built. 

 The section of this terrace, as shown by a well 55 feet deep, at Levi Case's former residence in 

 the west part of the village, about a sixth of a mile southeast from the ferry, is as follows: soil and 

 gravel, 3 feet; yellow clay, 3 feet; Shakopee limestone, of the usual character, hard, yellowish-buff 

 in color, partly siliceous and cherty, in beds from a few inches to one or two feet thick, 25 feet; 

 and soft, white Jordan sandstone, 24 feet and extending lower, containing water, which fills the 

 well to a depth of nine feet. At Charles Schwartz' limekiln, in the N. W. J of section 27, Ottawa, 

 a mile north of the village, the bluff composed of these strata rises 55 feet above the Minnesota 

 river, which flows at its foot. This bluff also reaches a quarter of a mile or more southward with 

 nearly the same hight. Its upper 10 to 15 feet are the yellowish Shakopee limestone, enclosing 

 occasional sandy patches and layers, levelly stratified, in beds from two or three inches to a foot, 

 or rarely more, in thickness. The sandstone, as usual, is friable, partly fine and partly coarse, 

 and consists almost wholly of water-worn quartz grains. It is level in stratification, but often its 

 horizontal layers show an oblique lamination. It is mainly white, but in some parts is stained 

 yellow by iron-rust; and it is streaked with green and pink in its upper one or two feet, next to 

 the limestone. By the recent undermining of this bluff, the sandstone is shown to extend to the 

 level of the river, being thus at least 45 feet thick. 



An outcrop of the Jordan sandstone alone is found at William Matheny's house, about 

 twenty-five rods east of the Ottawa ferry, having an extent of some fifty feet, but not exposing 

 more than five feet in vertical thickness. Its hight is about 35 feet above the river. The upper 

 layer, eight inches thick, is more cemented and harder than ordinary, and of a pink color; while 

 the lower part is softer, friable and white. The horizon of this ledge is probably the top of the 

 Jordan formation; for Prof. Winchell states that a little ravine, cutting the bluff a mile farther 

 north, near Schwartz' kiln, shows the upper portion of the sandstone there to be a hard, reddish 

 bed, one foot thick, underlain by the usual white, crumbling sandrock. 



Cretaceous clay. Hollows and crevices in the Shakopee limestone at 

 Ottawa have been filled by clay, which is commonly white or, before 

 weathering, light bluish or green, but on Cherry creek is mostly a red 

 ocher, colored by the anhydrous sesquioxide of iron. These deposits are 

 believed to be of Cretaceous age. They are similarly exhibited in water- 

 worn cavities of this limestone in Kasota and Saint Peter, and in Mankato 

 and South Bend, Blue Earth county; and in the report of that county a 

 more full notice of their character and probable origin has been presented. 



At John R. Clark's quarry in Ottawa, a vertical seam or crevice in the limestone, one or 

 two feet wide, extending six feet and more in depth, the bottom not being reached in this quar- 

 ry, and exposed along a distance of eight rods in nearly a straight course from east to west, is 

 filled by white clay of this kind. Nearly in the direction of this crevice, the same white clay was 

 found about twenty-five rods farther east, in Charles Needham's well, filling a similar crevice or 

 the continuation of this, in the limestone. 



A half mile south of Ottawa, Cherry creek has cut a channel or valley about 20 feet deep in 

 this terrace, its upper ten feet being the Shakopee limestone, with the Jordan sandstone below. 

 In the lower part of this limestone, along a distance of an eighth of a mile, are frequent water- 

 worn, pocket-like cavities, which are filled with this clay, partly white, but in more places brick- 

 red and suitable for paint. It has been so used, and is said to work well, and is durable. 



Glacial and modified drift. 



The thickness of the drift-sheet which covers Le Sueur county, except- 

 ing the Minnesota valley, where it has been eroded, is from 150 to 250 feet. 

 It is mainly till or the unmodified deposit of the ice-sheet, but encloses oc- 



