'Fauna of the Morrow Group 71. 
given. Acanthocladia is not known to occur below the Penn- 
sylvanian strata. 
The genus Rhomhopora is very abundant in the mid-Carbon- 
iferous limestones, especially those that are somewhat arena- 
ceous. Two of the Morrow species, R, attenuata and R. tahulata, 
are typical Mississippian forms, characteristic of the Keokuk 
and Chester horizons, which have not previously been observed 
in Pennsylvanian rocks. R. lepidodendroides, on the other hand, 
is typical of the Coal Measures through which it ranges in great 
abundance and has been identified from the Molas and Hermosa 
limestones of Colorado. The fourth member of this genus is a 
new species with indefinite affinities. 
The remaining bryozoans belong to the family Cystodictyo- 
nidae. Cystodictya is represented by four new species whose 
relationships are about as close to the members of the genus 
occurring in the earlier Carboniferous as to those in the later. 
Two species of Coscinium have been identified, both of them new. 
This genus has not been reported from the Pennsylvanian of 
North America and occurs very sparingly in Mississippian, 
although more abundant in Devonian, formations. It was, how- 
ever, first described by Keyserling^'^ from two species noted as 
occurring in the “Bergkalk’’ of the Timan Mts. The limestones 
from which they were obtained, in association with Fusulina, 
are described-® as overlying others in which Spirifer mosquensis 
and Chaetetes radians are the characteristic fossils. They are 
therefore to be correlated with the middle or upper Pennsyl- 
vanian rocks of North America. Tschernyschew^® also cites 
three species of the genus in his faunal list from the Schwagerina 
zone in the Timan Mts. Prismopora and Glyptopora are each 
represented by a new species. The former genus is known to 
range throughout the Carboniferous strata but the latter has 
heretofore been reported only from Mississippian formations. 
The Morrow fauna is in large degree a brachiopod one, not 
because of the abundance of brachiopod species but because of 
the great numbers of individuals of nearly every species of this 
class. No representatives of the Atremata occur here and the 
Neotremata are very scantily represented by two species of 
Orhiculoidea. O. missouriensis is a common form in the Coal 
Measures of the central states, occurs in the Park City forma- 
