llevlein of Recent Geological L'derottire. 315 
Anomid, is a commoa fossil of the upper beds of the Jurassic. Mr. Hill 
gives only one species (ind.) in this uncertain horizon, and that is in 
the Trinity sands. 
Tiirritelhi. Is a good Cretaceous genus, and if correctly identified goes 
far to prove the Cretaceous age of these beds. Mr. Hill has it running 
from the "lower beds" of the Fredericksburg division to the Xavarro 
beds in the upper Cretaceous. 
Cordium JuWniiim. Also ranges from the Jura to the Chalk. 
Pleuroeeni. Found also in the Trinity (Hill). May be a Cerithium or a 
Nerinea, both Jurassic genera (Marcou). 
^erpuld. Basal beds. Not mentioned by Hill. 
Trigonia rrenuldtd. According to Hill ranges from the "basal beds"' to 
the Comanche Peak chalk. 
The Glen Rose member is wedge-shaped and runs out toward the west 
allowing the Paluxy to lie directly on the Trinity, when the Paluxy is 
preserved. In other cases both the Glen Rose and the Paluxy are want- 
ing, and the "Texana bed,' of the Fredericksburg division, then comes 
immediately into superposition on the Trinity of the Bosque division. 
Notwithstanding this break in the order of stratification, which, how- 
ever, Mr. Taff does not seem to consider an unconformity of the Freder- 
icksburg on the Bosque, but rather an incident of continuous sedimenta- 
tion, and notwithstanding the partial alliance of the fauna with the Jur- 
assic, and the non-characteristic features of the other fossils he has 
named, Mr. Taff assigns the Bosque to the Cretaceous on the following 
grounds: 
"That the Trinity sand is Cretaceous and represents the littoral depos- 
its of a part of the loAver Cretaceous series, has evidence in the facts that 
its beds abut against the pre-Cretaceous continental contour ; that its 
beds conform to and blend with the undoubted Cretaceous Glen Rose 
limestones ; that its component materials are local, and have their origin 
in the paleozoic as a strictly near-shore rock ; and further, that it con- 
tains fossil fauna and Mora tliat range through superimposed beds of 
sand and limestone." 
There is, however, room to question wliether the (41en Hose is "un- 
doubted Cretaceous," and whether all the other "facts" mentioned 
would not hold true of the Jura, in case the Jura were supposed to ex- 
tend to the summit of the Bosque division, or at least to the summit of 
the "lower beds "of Hill. 
We know^ nothing of this subject from studies in the field. AVe take 
the facts and all the evidences as they are given l)y others. We have 
endeavored to call attention to the principal point of difference between 
Mr. Marcou and Messrs. Cummins and Taff, and we are constrained to 
conclude that the ((uestion is still an open one. Mr. Cummins' fossils 
seem to be from strata that lie above the actual Tucumcari stratum, 
although still embraced in beds which Mr. Marcou placed in the Juras- 
sic — indeed Mr. Cummins admits that he "did not find the Cretaceous 
fossils below the (xryphjea ftucumcari] beds." Therefore they were 
from strata above, and as some of them are identical with those which 
