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IOWA ACADEMY OP SCIENCE 
is correlated with the Oklahoman series of Kansas, a sequence, over 3500 feet 
in thickness, of sandstones and limestones, which carry the only organic forms 
known from this country representing the original Permian faunas of eastern 
Russia.® 
As at present understood the Red-Beds, which succeed the thick Guadalupan 
series on the hackslope of the tilted block forming the Guadalupe mountains, 
are the true southern extension of the Cimarronian Red-Beds, that a little farther 
to the eastward, in the Pecos valley, are followed by Triassic Red-Beds. If this 
interpretation of the stratigraphy of the southern New Mexico region be cor- 
rect then the entire Guadalupan series, representing at least 3500 feet of strata, 
are missing in the central Kansas section, and there are probably unconform- 
able relationships existing between the Cimarronian and Oklahoman series of 
that section. 
In central Kansas no one, so far as I am aware, has ever before intimated 
that the Cimarronian series rest unconformably upon the Oklahoman series. At 
best it would be in that region very difficult to make out such relationships. 
Passing now to north-central Iowa it is possible that we have a clew to the 
true situation in the isolated area of the Fort Dodge gypsum deposits. If the 
gypsiferous beds of Fort Dodge are really Late Carbonic in age instead of 
Cretacic age, as Wilder^ has recently attempted to show, we have right here in 
Iowa unexpected data for the solution of the Red-Beds problem. It has been 
shown^ however, that Wilder’s argument for considering the Fort Dodge gypsum 
deposits earlier than Cretacic in age is not supported by adequate facts derived 
from his observations on the region, that there are general stratigraphic con- 
siderations which he did not touch upon that make the suggestion m 9 re worthy 
of special and exact inquiry than any which he has discussed. It must also 
be remembered that the gypsiferous beds at Fort Dodge are not Red-Beds in 
any sense of the word, nor does their slight pinkish tinge at all suggest the 
true Red-Beds of Kansas. 
Of the other great “Red-Beds” formations of the southern Rocky Mountain 
region special mention should be made of the Bernalillo shales,^ nearly 1000 
feet in thickness, which immediately overlie in the typical locality in the Sandia 
mountains the dark blue and black limestones. These shales carry abundant 
fossils which correspond faunally with those found in the upper part of the 
Oklahoman series of Kansas. Besides these Red-Beds there have been recog- 
nized in the region other great red colored terranes in the Cretacic section, in 
the Tertiary section and in the Devonic section, as already stated. 
6. Journal of Geology, Vol. XIV, p. 296, 1906. 
7. Iowa Geol. Surv. , Vol. XII, p. 63, 1901. 
1. American Geologist, Vol. XXX, p. 99, 1902. 
2. Kept, of Governor of New Mexico to Secretary of the Interior, for 1903, p. 339, 1904. 
