3i8 The American Geologist. May, i90(i 
*Inoceramus cripsii Mantell. 
*I. confertim-annulatus Rcemer. 
*I. problematicus Schlotheim. 
Cardium congestum Conrad. 
Tapes hilgardi Shumard. 
Cvprinieria crassa Meek. 
Chemnitzia ? texana Meek. 
Placenticeras guadalupas (Roemer). 
Placenticeras placenta (Dekay). 
Baculites anceps Lamarck. 
Some of these supposed discrepancies in the horizons in which 
species ate found in the two adjacent regions are doubtless due to in- 
correct identification on one side or the other, or to dependence on 
statements as to stratigraphic range, published many years ago and 
since disproved, but in the case of the species of Inoceramus and the 
three ammonoids, no such explanation is possible. It is evident to any 
one at all familiar with the Cretaceous faunas of Texas and northern 
Mexico, that tlie Mexican geologists have either been mistaken as to 
the localities and associated faunas in which these species occur, or else 
they have assigned a great thickness of post-Comanche strata to the 
Comanche series. The reviewer has collected them, both in Texas and 
northern Mexico, always in beds lithologically different from the Co- 
manche and unquestionably above it — in the case of the ammonites 
many hundreds of feet above it. The assertion is confidently made that 
not a single one of the species in the above list, when properly r-is- 
criminated, will be found to occur in both the Comanche series and the 
overlying Upper Cretaceous beds. When such fossils as these are sup- 
posed to occur in the Comanche it is not surprising that nearly the 
whole series is referred to the Upper Cretaceous by our author, 
whose provisional classification places the Washita division in the 
Turonian, the Fredericksburg in the Cenomanian, and the Trinity in 
the Aptian-Urgonian. After quoting the opinion of Heilprin that 
there is no Lower Cretaceous in Texas, of Douville that the Caprina 
limestone is upper Gault or lower Cenomanian, of G. Boehm, that 
the Escamela limestones are upper Cenomanian. and of J. Boehm that 
the Comanche series is partly Cenomanian, Bose says: "Thus it is 
shewn more and more that the geologists and paleontologists who oc- 
cupy themselves with the Comanche series and the limestones of 
Orizaba are inclined to the opinion that they belong to the Ceno- 
manian." It should be stated, however, that none of the authors whose 
opinions i^re quoted has had the opportunity to become acquainted 
wiih the Comanche faunas and their studies have- been confined to a 
few s;:ecimcns of certain groups in which they were interested. When 
they have dealt with the Rudistie and Chamidse of the so-called Caprina 
beds, their comparisons have often been with formations in Europe 
whose age has long been debated and may still be questioned. 
♦"Transition beds between W^ashita and Black Prairie Series in 
northern Mexico." 
