SO-CALLED CRETACEOUS DEPOSITS IN MINNESOTA 681 
cribed from the neighborhood of New Ulm on the Minnesota 
River, but since they have afforded no further conclusive 
evidence, and since they too lie on the border or outside of what 
should be called southeastern Minnesota, I pass them by. 
Again, the supposed Cretaceous, which occurs farther down the 
Minnesota River valley at and below Mankato, might be passed 
perhaps justly with a denial that it is Cretaceous. Of course 
Cretaceous materials and fossils may be found in drift there and 
elsewhere in the state. But the beds of fine clay, containing 
some sand, which are on and in the Shakopee and Oneota 
dolomite formations, bear no fossils. They are like mere 
pockets of residuary clays from limestones and dolomites. 
They occur as white or variegated clays in the seams or in 
pockets or resting irregularly upon the iron-stained surfaces of 
the dolomites. Gravels of later age, possibly from early glacial 
drift, have been also described as Cretaceous, while others are 
possibly early Pleistocene, possibly Cretaceous. There is little 
or no conclusive evidence of the age of these small deposits. 
They need therefore no detailed description here, but a full 
account of them can be found in Final Report, Vol. I, p. 432; 
Vol. II, p. 127, Minnesota Geological Survey. 
The reported Cretaceous at Austin, Mower county, is more 
important, because upon its character has depended the coloring 
of several counties on the geological map. Austin lies about 
60 miles southeast of Mankato, 85 miles therefore in the same 
direction from New Ulm. The map coloring from Mankato to 
Austin depended upon the occurrence of supposed Cretaceous at 
Austin. Here occurs a variegated clay ranging in color from 
pea-green to bright red and yellow, resting upon a limestone or 
dolomite of Devonian age. It has not however been found in 
place, but is always, as far as known, involved in the glacial 
débris. Whatever the origin of this clay, it is now glacial drift, 
a Pleistocene deposit, and therefore not properly to be mapped 
as Cretaceous. 
Regarding the question whether or not these clays were 
derived from Cretaceous formations, it must be said that the evi- 
