46 
BULLETIN OF THE LABORATORIES 
‘ Spirifera, sp? 
(Plate II, Fig. 6,) 
A very transverse species is indicated by the cast figured, which - 
can not be identified with any known coal-measure species. The na- 
ture of the specimen forbids making it the subject of a formal descrip- 
tion. It is clearly related to Waverly forms. 
Sub- GENUS martinia, McCoy. 
Dorsal margin shorter than the width of the shell, the angles of 
the hinge-margin shortly rounded; surface smooth or with punctate 
(spiniferous?) concentric lines, often with less distinct sub-epidermal 
radiating striae ; spiral lamellae small. 
Species o^ this group appear in the Silurian and continue into the 
carboniferous. 
i. Spirifera {Martinia) planoconvexa, Sch. 
(Plate I, Fig. 12.) 
This little shell was found but once in the shales above the Flint 
Ridge coal. It is one of the commonest and most widely distributed 
coal-measure species, very possibly identical with S. Urii^ Fleming, of 
Great Britain. 
Length and breadth nearly equal; the lateral and lower (front) 
margins forming a continuous arc like a segment of a circle; ventral 
valve rather tumid, being most convex near the middle ; beak pro- 
duced beyond the hinge line, incurved; foramen narrow; area con- 
cave; dorsal valve flat with minute somewhat incurved beak; surface 
of both valves granular, with few, rather indistinct concentric lines. 
2 . Spirifera (Martinia) lineata, Martin? 
(Plate I, Figs. 13a, T3b, 13c.) 
The second species is considerably larger than the first, indeed, it 
is not certain that two species are not here confused. That figured on 
Plate III, Fig. 23, was imperfect, but so far as preserved seemed to 
agree with S. lineata, as identified by American writers. In this 
specimen, which was largely denuded of the shell, the radiating striae 
were very evident and yet on such portions as still retained the shell 
