Fauna of the Morrow Group 
69 
the Cherokee shales at the base of the Kansas Pennsylvanian 
series. Chaetetes is abundant throughout the world in the later 
Paleozoic limestones and the form here recorded is known from 
the Coal Measures of Tennessee, Missouri, and Kansas as well 
as from the Pennsylvanian limestones of several western states. 
Blastoids are represented in the Morrow fauna by two species 
of Pentremites, a genus which has been supposed to occur only 
in Mississippian strata. The individuals of the genus are so 
numerous in the Brentwood member that this formation was 
termed the Pentremital limestone by the geologists of the earlier 
Arkansas Survey. The genus is present, though rare, in the 
Hale formation but is not known from the Kessler. This assov 
ciation of the genus with forms of Pennsylvanian age which 
also occur in the Brentwood limestone is unique. 
Crinoids are abundantly indicated by the numerous fragments 
of stems and plates which contribute to the limestones of the 
group but are only rarely preserved with sufficient completeness 
to afford an opportunity to determine their affinities. Hyclreio- 
nocrinus is represented by a few plates which offer no clue as 
to specific relationships. The genus is present throughout the 
Carboniferous terranes. Cromyocrinus , represented by a new 
species, has been previously reported in North America only 
from Mississippian formations while the species of Eupachy- 
erinus most strongly suggested by the isolated plates which are 
referred to that genus is present in the Coal Measures of Mis- 
souri. Delocrinus is represented by three species here described 
for the first time. This genus has been identified only from the 
post-Chester formations with the possible exception of a little 
crinoid from the Kaskaskia of Tennessee which is doubtfully 
referred to it by Rowley. Stereohrachicrinus is a new genus 
provisionally referred to the Poteriocrinidae, the most common 
of the families of Carboniferous crinoids. 
The presence of echinoids in the Morrow seas is recorded by 
a few of the spines characteristic of Archeocidaris, a genus 
which ranges throughout the entire Carboniferous series. 
Bryozoans make up a large proportion of the Morrow fauna 
and are especially abundant in the limestone lenses of the Hale 
formation. The Cyclostomata are represented by an undeter- 
mined species of Fistulipora, a genus which is quite common in 
