ee ae ee MT SE ETS a ee BC ene eve eS Bes 
F, V. Hayden on the Cretaceous rocks of the West. 178 
Ridgely, says: “ Proceeding westward from Fort Ridgely, I had 
no opportunity of seeing any other formation than the prairie 
for about thirty miles. At this point near where we crossed the 
Big Cottonwood River, there is an exposure of rock in the bank 
of the stream; and at a short distance farther on, some explora- 
tions had been made for coal, and a shaft had been sunk to the 
depth of more than one hundred feet. The materials throw wn 
out of this shaft consisted of a dull greenish argillaeeous sand, 
with calcareous nodules, together with irregularly lamina 
sandstone containing vegetable remains. The order of deposits, 
as given to me by Mr. =e who superintended a part of the 
working, was as follow 
. Ironstone; 1 ft, 2 aie 
Sand, clay, ete.; 40 ft. 
Earthy coal ;* I fe 8 inches. 
Sand, clay, e 
Sandstone in gion and diagonally Jaminated layers, with some- 
times calcareous concretions, and containing plant remains; 5 ft. 
A Caleareous sandy clay of variable color and character; 20 ft. 
Sandstone in loose tMin layers of three or four inches ; 4 ft. 
ene with coaly seams near the bottom; 16 ft. 
0. tee o quicksand to bottom of shaft. 
“In the river bank, at a quarter of a mile distant, and at a 
level 30 or 40 feet below the ground where the shaft began, there 
is the following exposure: 
. Loose ironstone in nodules and concretions, more or less 
mixed with drift and pebbles; 1 
Calcareous clay ; 6-8 ft. 
Earthy coal; 8 ange 
Clay as Wao coal ; e 
Yellow or — ha and cla ay 8-34 ft. 
Perpginous sandstone in epee are and diagonally laminated 
o level of river; thickness un 
. This sandstone appears to be — same as that containing the 
vegetable remains met with in the shaft; and though I did not 
find plants in it at this point, I was informed that specimens had 
n found there; and at another place on the Cottonwood I 
BOPIe Repo 
bend 
& VIR go 19 
imal them to be quite common. Near the previous exposure, 
* An analysis of this coal, - Prof. T. ear! Hunt, gave the genet: results : 
Fix 
pe npaae “ e ; ‘ i ‘ ; j 257 
ts 48-2==1000° 
; the ore of strata near yp ak of the Retence ivi: there is a stratum 
of similar earthy coal three rset: ee 
+ This ferruginous layer does not appear to belong to the regularly stratified 
deposits, as it overlies, irregularly ly, the veges of the successive beds, and has been 
deposited after the denudation had taken p 
Am. Jour. Sc1.—Srcoxp Series, VoL. frat No. 128.—Muxcu, 1867. 
23 
