102 The American Geologist. August, 1894 
as he sometimes calls it. The "Caprina limestone' 1 cannot be 
separatee! from the "Gh'yphcea pitcheri limestone" at Comet 
creek and is the basal bed of the Lower Cretaceous. All tin- 
strata below do not belong to the Cretaceous, but to the Jura 
<>r New Red sandstone. There is a great break of the strata. 
with a complete change of geographical distribution in north- 
ern Texas between the group of strata containing the Capro- 
tiini texana Koeni. and the Gryphasa roemeri Marc, (formerly 
called by Roemer and Marco u the Gryphasa pitcheri) and what 
has been called by Mr. Hill the Fredericksburg and Trinity 
divisions, and by me at the Tucumcari area the Jurassic 
formation of North America. 
The subdivision introduced at different times in the Fred- 
ericksburg seems to be local, simply different fades of the 
upper part of the Trinity. Correlations between the Jurassic 
strata of the Tucumcari and the Trinity and Fredericksburg 
divisions have not yet been established. It is a good field to 
work in. The fauna of the upper part of the Jurassic strata 
of Pyramid Mount at the Tucumcari. thanks to the collection 
made there in 1889 by Prof. A. Hyatt, is now well known: 
and with such characteristic fossils as Gryphasa <lihit<it<i. var. 
tucumcarii and Ammonites belknapii, it must be easy to define 
with exactness and distinguish in Texas the Jura and the 
Neocomian. All the strata that exist below the zone of 
Gryphasa tucumcarii and Ammonites skumardi, and that zone 
itself, are older than the Cretaceous system and belong to the 
Jurassic system. All the strata above, containing Ca j>r<>/ ina 
texana and Gryphasa roemeri (formerly the Gryphasa pitcheri 
of Roemer and Marcou), belong to the Cretaceous. The Lower 
Cretaceous in Texas is composed of what Mr. Hill calls 
the Washita division (including in it his "Caprina limestone*) 
andiswhatl have called, since 1858. the American Neocomian. 
One word more, about a question of priority which seems 
to have escaped Mr. Hill, although I have privately called his 
attention to it. Mr. Hill refers the species described and fig- 
ured by Roemer, in ls.ri. and by me in 1855-58, under the 
name of Gryphasa pitcheri to a species figured twenty-five 
years later, in L880, by Dr. C. A. White under the name Gry 
phasa'forhiculata, as a new species, confounded before with the 
G. pitcheri. Roemer made the mistake to refer a Gryphasa 
