Correspondence, 
363 
peculiar soft and loamy and "brick-dust" soils which there character- 
ize the latter formation. Only two horizons of the Taloga observed in 
that part of Oklahoma need here be especially designated. These are 
V)oth of gypsuqa of poor quality, and belong to the bluffs that rise on 
the south side of the Canadian river, in "D" county, in view from the 
post-office of Butte. One of these appears in the brow of the bluffs, 
about ? 250 (between 215 and 285) feet above the river, and has a thick- 
ness of 3 or 4 feet. The other, much more limited in horizontal extent, 
occupies a position 90 or 200 feat lower, and has a thickness of only a 
foot or two, but is underlain with 4 or 5 feet of red gypsum-clay. They 
may be called respectively the One Horse and the Old Croio gypsum af- 
ter the two fords of the Canadian river which (after Indians resident 
near them) are known as the '■'On-:- Horse crossing" and the "0/d Croin 
crossing," the upper bed being named from the upper ford, — One Horse 
— and the lower from the lower. The One Horse horizon has been fol- 
lowed for only a short distance, but is probably a horizon in the sense 
of a stratigraphic level in which gypsum is continuous or recurrent 
within a considerable extent of outcrop. The Old Crow gypsum appears 
to be only a small lens. It is not yet known whether either of these 
gypsum beds may approximately correspond in position with the Beaver 
gypsum of Beaver county, as the elevations all above the base of the 
Kiger, are unknown. That all three horizons are in the Kiger division, 
and that those of "D"' county are well up in the Taloga formation, is all 
that can now be considered certain; but there are some considerations 
that seem to indicate a lower position for the Beaver. 
In closing, I present in tabular form what, in the light of these new 
and all earlier observations, seems to be the most broadly adaptable 
CLASSIFICATION OF THE ROCKS OF THE CIMARRON SERIES. 
Divisions. 
Kiger. 
Formalions. 
Salt Fork. 
I Taloya. 
\ Day Creek. 
y Red Bluff. 
Dog Creek. 
[Stony Hills.) 
Cave Creek. 
Glass Mountain. 
Kinyjisher. 
Colorado Springs. 
Suhformations. 
Quite variable with 
locality. 
None. 
None determined. 
♦Chapman dolomite. 
♦Amphitheatre dolomite. 
k Shimer gypsum. 
■\ Jenkins clay. 
( Medicine Lodge gypsum 
Fk)wer-pot shales. 
♦Cedar Hills sandstone. 
Salt Plain. 
Harper. 
F. W. Cragin. 
♦Starred suhformations in the table are not known to be clearly recognizable out- 
side of the type locality. 
