574 THE GEOLOGY OF MINNESOTA. 



[Cretaceous beds. 



reaching in some places 30 to 40 feet above the river. The bedding is lenticular and inconstant. 

 A layer of yellowish brown, ferruginous and more firm sandstone, with a dip of 3 or 4 toward 

 the west, exposed here about ten feet above the river, contains plentiful impressions of dicoty- 

 ledonous leaves of numerous species. A considerable collection of these has recently been made 

 by Prof. Winchell, and determined by Dr. Leo Lesquereux, who states in correspondence that his 

 observations of fossil leaves in 1856* were at this locality or in its immediate vicinity. The list is 

 as follows: Magnolia altemans, Heer, Andromeda Parlalorii, Heer, Cinnamomum Scheuchzeri, 

 Heer, Platanus prim&va, Lesq., Salix protecefolia, Lesq., Populus cydophylla, Lesq., P. elegans, 

 Lesq., P. Lancasti-iensis, Lesq. (probably the same with P. cordifolia, Newberry), P. litigiosa, 

 Heer, Populites cyclophyllns, Lesq., Protophyllum crednerioides, Lesq., Cissus sp. nov., Laurus 

 sp. nov., Pinus sp. nov., and fragments referred doubtfully to Persea and Ficus. Nine of these 

 species, according to Dr. Lesquereux, have been recognized in the Dakota group, the lowest of the 

 Cretaceous series, in Nebraska and Kansas, and two in the same group in Colorado. 



Clay and an underlying more sandy deposit, which have been used together for the manufac- 

 ture of fire-bricks, occur in the base of the north bluff of the Cottonwood river south of New Ulm. 

 The entire section of this bluff is given by Prof. Winchell in the second annual report. 



Section on the Cottonwood river south of New Ulm. 



"1. Hardpan drift, made up of clay and stones, seen about 30 feet. 



2. White sand, the age of which is uncertain, containing irony concretions and 



deposits. It is somswhat indistinctly stratified obliquely, like drift sand, 

 and has some coarse grains. Its position in reference to the overlying hard- 

 pan drift, together with its thickness and purely white color, indicates its 

 age to be Cretaceous 100 feet. 



3. Blue clay, containing some siliceo-calcareous, irony lumps; said by Mr. Dauf- 



fenbach to hold some coal; mixed with No. 4 for making fire-brick 4 feet. 



4. Fine, somewhat gritty clay, largely aluminous. This is white, and when 



long submerged, soft and fluid-like, but when dry has to be quarried by 

 blasting. This mixed at the rate of two-thirds with one-third of No. 3 

 makes a fine, white fire-brickseen 12 feet. 



Total hight of bluffs '146 feet." 



"The above section varies in short intervals. . . . About half a mile further up the river 

 a sandstone outcrop was encountered. It rises in a bluff immediately from the water, on the op- 

 posite side of the river. In this sandstone, which here appears firm and massive, and which is 

 probably the equivalent of No. 2, of the foregoing section, are many irony mud balls, or concre- 

 tions, having a fancied resemblance to plums or bananas. They vary in shape and size. They 

 have been gathered as fossil 'fruits,' and sent east as rare curiosities." 



The valley of the Minnesota river was explored by Prof. Winchell in 

 1873, and the greater part of the descriptions of the Cretaceous strata, as 

 here presented, are from his report for that year. Some additional obser- 

 vations and information were gathered by the writer in 1879 and 1880. 



In Cottonwood township, Brown county, near its east line, a bluff on the south side of the 

 Minnesota river, situated on the land of John Gruebel, four miles below New Ulm, is described 

 by Prof. Winchell, as follows: 



Section in sec. 2, Cottonwood. 



" 1. Black alluvium 2 ft. 



Passing below into 



2. Clayey alluvium, of a light-brown color 4J ft. 



3. Bed clay, containing some sandstone in masses; stratified 2} ft. 



4. Belt of greenish sandy clay 1 ft 



U. S. geol. survey of the territories: vol. vi, The Cretaceous Flora, p. 6. 



