GIRTY, THE GUADALUPIAN FAUNA 
145 
alent horizons in the Mississippi Valley. If correlated with any part of the 
Kansas section, the equivalence is presumably with the upper beds, in view 
of the great thickness of the trans-Pecos series and the general character of 
the Hueeo fauna. The actual relations must be determined by stratigraphic 
or new paleontologic evidence. 
At one point in the preceding discussion it was stated that at the time the 
Guadalupian fauna was described, no stratigraphic facts were known which 
tended to determine the relationship of the Guadalupian series to the Carbon¬ 
iferous of the Mississippi Valley. To this statement one exception may be 
made. W. F. Cummins 1 had already traced the Permian and the Triassic 
(Dockum group) of central Texas around into the trans-Pecos region, 
where they were found to occupy a position suprajacent to the Guadalupian. 
C. N. Gould’s work, published as Water-supply Papers of the U. S. Geologi¬ 
cal Survey, 2 does not bear so much upon this point and was hardly accessible 
to me at that time, because my report was nearly three years in the hands 
of the editors, mostly in proof, so that his earliest report must have been 
coming from the press just as mine was going into it. The failure to discuss 
Cummins’s conclusions in their bearing on the correlation of the Guada¬ 
lupian beds was due to oversight rather than to an intentional disregard of 
stratigraphic evidence. Nevertheless, the peculiar and individual features 
of the Guadalupian faunas were so impressive that I think I should have 
been disposed to believe that some mistake had been made in mapping the 
Texas formations since the work was of a reconnaissance nature, since it 
was without fossil evidence (in fact, when we consider the nature of the 
Guadalupian fauna, it may in a sense be said to have been contrary to fossil 
evidence), and since it involved the tracing, over a long distance, of strata 
peculiarly difficult to follow owing to lithologic changes at the same horizon. 
Under present conditions, while the considerations mentioned still 
obtain, the objection resident in the peculiar facies of the Guadalupian fauna 
is largely removed by the facts recently brought to hand, and this becomes 
about the only line of evidence at present available, which links the Guada¬ 
lupian beds with those of the Mississippi Valley. The result of a summary 
of this evidence is surprising. In Cummins’s terminology the Permian 
consists of the Wichita, Clear Fork and Double Mountain formations, the 
latter being the highest. Now, according to the same author, the upper 
part of the Wichita is the Fort Riley limestone, 3 which is the middle portion 
of the Chase or basal group of the Kansas “ Permian ”. Consequently, if this 
tracing is correct, the Guadalupian beds represent a horizon below the base 
1 Geol. Surv. Texas, Third Ann. Rept., p. 211; also N. F. Drake, idem., pp. 227 et seq. 1891. 
2 Nos. 148, 154, 191. 
3 Texas Acad. Sri., Trans., vol. 2, p. 98. 1897. 
