70 
Kirtley F, Mather 
Mississippian but less numerous in Pennsylvanian rocks. The 
Trepostomata are somewhat more abundant, with two species 
of Stenopora and one of Anisotrypa. Of the three only one, S, 
tuberculata, is identified specifically. It is a form which fre- 
quently occurs in the St. Louis and Chester horizons of the cen- 
tral states and has been reported from the Pennsylvanian of 
Nebraska and Colorado. The second of these two genera has 
not heretofore been described from beds younger than the 
Chester. 
By far the larger percentage of the Morrow bryozoans belong 
to the order Cryptostomata and the family Fenestellidae. Fenes- 
tella is represented by three species, two of which are new, and 
the third, F. serratula, recorded as ranging from the Keokuk to 
the Chester in the Mississippi valley, has not been previously 
known to persist into Pennsylvanian times. The highly special- 
ized genus, Archimedes, represented by a new species, is occa- 
sionally found in the Brentwood horizon. Like Pentremites, it 
has been supposed to be diagnostic of Mississippian times. Four 
species of the genus, however, occur in the Timan Mts. in the 
Schwagerina zone, the uppermost of the Carboniferous lime- 
stones of Russia, and it has been reported^^ in the Lower 
Aubrey limestone of the Uinta Mountains associated with an 
Upper Carboniferous fauna. Girty, also, states^^ that he has 
collected the genus in abundance in the Bingham district, Utah, 
in rocks which he believes to be of Pennsylvanian age. Eleven 
species of Polypora, all new but one, have been distinguished, 
P. elliptica is present throughout the Coal Measures of Missouri, 
Kansas, and Nebraska, ranging from the Ft. Scott to the Neva 
limestone in Kansas, The genus Phyllopora has heretofore been 
reported from strata younger than the Devonian at only one 
locality in North America. It is stated-® to occur in the Embar 
formation, probably of Permian age, in Wyoming and has been 
described from occurrences in late Paleozoic rocks in Great 
Britain and India. Two species, both undescribed, are here 
referred to the genus. 
The family Acanthocladiidae is represented by five forms, 
three new species of Septopora, a genus present in both Missis- 
sippian and Pennsylvanian times, an Acanthocladia, and a spe- 
cies referred to a new genus to which the name Dictyocladia is 
