Fauna of the Morroiv Group 
77 
Gastropods are not plentiful in the Morrow fauna but like the 
other classes of invertebrates they show conspicuously a mingling 
of Mississippian and Pennsylvanian types. Lepetopsis cheste- 
rensis, as its name implies, is a typical Chester form and the 
individual found in the Morrow presents little or no variation 
from the earlier ones. Bellerophon crassus var. iveivokanus is 
known from the Wewoka limestone, a mid-Pennsylvanian for- 
mation of Oklahoma, and from the Ames and Brush Creek lime- 
stones in West Virginia. The typical variety of the species is 
present in nearly all collections from the Coal Measures. The 
smaller Bellerophon, compared with B. sublaevis, is very closely 
related to that common Mississippian form. Euphemus carho- 
imrius ranges throughout the entire Kansas section and is char- 
acteristic of the Pennsylvanian of the Mississippi valley region. 
Worthenia tabulata is likewise a Pennsylvanian form with a 
wide distribution and long range. Euconospira is abundant in 
the Pennsylvanian formations but is known in Mississippian 
beds from only one species which occurs in the Fayetteville 
shale. It is represented in the Morrow by a new form, 
Straparollus is represented by a number of individuals which 
are very closely related to S. spergenensis, an Upper Mississip- 
pian species, while Euomphalus catilloicles is another fossil char- 
acteristic of Pennsylvanian strata in which it has a long range 
and wide distribution. Strophostylus subovatus occurs in the 
Coal Measures of Illinois and the Hermosa limestone of Colorado. 
The single individual from the Morrow is referred to it with 
little doubt as to the correctness of the identification. Platy- 
ceras parvum is the most abundant of the Morrow gastropods. 
It occurs in the Coal Measures of the Mississippi valley quite 
generally and is reported from certain of the Pennsylvanian 
limestones of the west. 
Three of the Morrow gastropods are turreted shells. Aclisina 
and Sphaerodoma range throughout the Carboniferous while 
Meekospira is apparently confined to Pennsylvanian formations. 
All three are very scantily represented in the fauna. 
Cephalopods are comparatively unimportant numerically but 
the four forms identified are of considerable interest. The spe- 
cies of Orthoceras resembles certain of the Mississippian mem- 
bers of that genus as closely as it does the Pennsylvania forms. 
