DEVONIAN FAUNAS. 301 
marked by fine, irregularly bifureating, raised, radiating strie, and 
by strong, more or less irregular, concentric wrinkles, which curve out- 
ward on approaching the cardinal margin. 
The dimensions of a large specimen are: length, 37 mm.; width, 
46 mm. 
' Remarks.—This species occurs occasionally in the lower chery lime- 
stone of the New Scotland beds, is of more common occurrence in the 
shaley members of the formation, but is most conspicuous in the Be- 
eraft limestone, where it occurs in great abundance. The species may 
always be recognized by its strong, concentric wrinkles, resembling, in 
this character, Leptena rhomboidalis, with which species it may some- 
times be confused when imperfectly preserved. L. rhomboidalis, how- 
ever, is always strongly geniculate towards the front, the concentric 
wrinkles being confined to the posterior, flattened portion of the shell, 
while in S. beckei the depressed-convex form of the shell continues to 
the margin, as do the concentric markings. The crenulated hinge-line 
of 8. becker would also always distinguish she two species, but this 
_ is a character which is rarely preserved. 
STROPHEODONTA sp. undet. 
There are in the New Scotland beds and the Becraft limestone, 
and especially in the latter formation, more or less numerous speci- 
mens of Stropheodonta, which doubtless represent several species. 
They are all so poorly preserved, however, that their surface characters 
have been practically destroyed, and it is not possible to identify them. 
One or two forms are possibly undescribed species, but much better 
material must be had before their characters can be made out satis- 
factorily. 
STROPHONELLA PUNCTULIFERA (Con.). 
Plate XXXIII., Fig. 9. 
See, also, p. 277. 
This species has already been described from the Coeymans lime- 
stone. he New Scotland and Becraft limestone specimens are similar 
in all respects to those of the preceding fauna, and their state of 
preservation is much the same, all the specimens observed being frag- 
mentary. 
