20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 134 
lation in the United States is with the fauna of the basal Word which 
contains the Leonardian elements Perrinites and Dictyoclostus bassi. 
In Russia the correlation is with medial to late Artinskian. 
Another and perhaps more positive correlation will be afforded by 
study of the fusulines which are common in the Permian rocks of the 
Grindstone-Twelvemile Creeks area. It is possible, however, that the 
correlation based on the fusulines will be at variance with the present 
one derived from study of the brachiopods. Correlations based on a 
single group of animals are seldom reliable unless the animal group 
used is an already established zone fossil. Zoning of the late Paleo- 
zoic has hitherto been based on the fusulines. The brachiopods of 
the Pennsylvanian and Permian, however, are still too poorly known 
to be reliable as zone fossils. They will increase in correlative value 
as more collections and critical studies are made. 
DESCRIPTION OF THE SPECIES 
In the descriptions full synonymies are not cited. Citation to the 
original description is generally given. This is followed by one or 
more references where full synonymies appear. 
Class’ GASTROCAULLA 
Superfamily OpoLacea Schuchert, 1896 
Family OBOLIDAE King, 1846 
LINGULA sp. 
Plate 1A, figures 1-3 
Shell small for the genus, length twice the width, strongly convex 
in anterior and posterior profile but slightly convex in lateral profile. 
Beak bluntly pointed ; sides gently rounded but anterior margin nar- 
rowly rounded. Interior with a long ridge extending along the axis 
of the valve nearly from the beak to about the middle where it ends 
at a callus swelling on the floor. Traces of two pallial trunks appear 
anterior to the callus. 
Measurements in mm.—Length 17.3, width at middle 8.8. 
Types.—Figured specimens, U.S.N.M. 125311, 125531. 
Localities —S50 ; U.O. 2204-3. 
Discussion—Lingula is rare in any Permian rocks in the United 
States and is apparently not frequently met elsewhere. This is a more 
elongated and more acutely pointed species than L. carbonaria expor- 
recta Girty from the Phosphoria formation in Wyoming. The ma- 
terial available is not sufficient for the establishment of a species, as 
it consists only of a pedicle valve and a crushed brachial valve. 
