Fauna of the Morrow Group 
83 
to the Morrow. What little is known of the fauna of the Wapa- 
nucka limestone of southern Oklahoma and of the Marble Falls 
limestone in the Llano-Burnett region is in harmony with the 
idea that those formations may prove, when better known, to 
contain homotaxial equivalents of the Morrow.* 
Ulrich has referred the Caney shale of the Ouachita region, 
Arkansas-Oklahoma, to the Pottsville and, as noted on page 65, 
has stated that a part of that formation is the equivalent of 
the Morrow. Woodworth^^ likewise places that formation in the 
Pottsville series. A comparison of the Caney fauna as described 
by Girty,^5 with the Morrow fauna as now known shows only 
one species, Productus cora, common to the two formations. It 
is evident that the fossiliferous portion, at least, of the Caney 
cannot be of Pottsville age. 
In the attempt to find contemporaneous marine faunas in early 
Pennsylvanian strata outside of North America one’s attention 
would naturally be directed toward eastern Europe with its great 
series of Carboniferous limestones. Among the known faunas 
from those terranes, that of the “Bergkalkschichten” of Mjat- 
schkowa, as described by Trautschold,^® presents the most strik- 
ing similarities to the Morrow. Those beds are referred to the 
upper portion of the mountain limestone series and the fauna 
is doubtless typical of the ''Spirifer mosquensis zone” of Russia. 
It would appear that its correlation with the Carboniferous suc- 
cession of North America is with the Pottsville rather than the 
Chester stages. 
* Since the above was written I have received from Mr. C. R. Thomas, 
of the Oklahoma Geological Survey, a small collection of fossils -from the 
Wapanucka limestone obtained at several localities in and near the Atoka 
and Coalgate quadrangles in south-central Oklahoma. Twenty-one species 
compose the fauna and all belong to genera found in the Morrow. Two 
are new species; eighteen are conspecific, or nearly so, with Morrow forms. 
The presence of Pentremites angustus, Rhipidomella pecosi, Productus 
nanus, Spirifer opimus, Squamularia perplexa, Composita ozarkana, and 
Myalina orthonota is conclusive evidence of the contemporaneity of the 
Wapanucka and Brentwood limestones. 
