46 
BULLETIN OF THE LABORATORIES 
of the surface. 1 "he surface is also more convex. There are about 
28 plise, four being on the fold and those of the general surface are 
simple, while those of the fold dichotomize. This species is smaller 
than S. striatiformis. Division III, near Newark. W. F. Cooper, 
collector. 
Spirit 6 T ivitichelli, sp. n. 
(Plate V, Fig. 2-3; Plate II, Fig. t6.) 
Mcst nearly resembling S. mesacostalis. Shell transversely elon- 
gate, gibbous; width from two to three times the height. Ventral 
valve quite convex mesially, strongly and evenly arched from the 
closely incurved and projecting beaks to the lower margin. The area 
is very narrow; hinge-line usually strongly produced, lateral angles 
mucronate; surface marked by about 15 rounded plicae on either side 
of the deep triangular sinus. (In one case a trace of slight fold in 
the bottom of the sinus was discovered, but, as all our specimens are 
casts, these might not usually be preserved if present. Dorsal valve 
less gibbous ; area very narrow, beak minute; surface most convex 
near the middle ; fold high, strongly defined, narrow, marked in the 
center by a deep groove. Surface ornamented by lamellose concentric 
lines. The close relationship with S. mesacostalis of the Chemung 
require, no comment. If the strata were adjacent the two would hard- 
ly be separated. A considerable number of closely agreeing speci- 
mens were found in conglomerate II, at Granville. Named in honor 
of the distinguished state geologist of Michigan. 
Spirifer sp (Cf. N. raricosta, Con.) 
f Plate I, Fig. 5 . ) 
A small species of Spirifer, resembling Spiriferina somewhat, or 
more nearly the species quoted above, is represented by the single 
fragment from an unascertained portion of the Waverly. As the spe- 
cies in question belongs to the corniferous horizon and ours has a 
greater number of plic^, it is improbable that they should proue iden- 
tical. 
