PALiEOZOIC FOSSILS. 



Orthis oblata ( new species). 



Palaeontology of NeAv-York, Vol. Hi, pi. 10, f . 1 - 14. 



Shell ( in the young state) longitudinally subovate, and varying 

 from circular to transversely oval in its stages of growth, re- 

 sujDinate : ventral valve convex at the beak, flattened in the 

 middle, and convex towards the front ; dorsal valve very convex 

 in the middle and toTsrards the beak ; beaks of the two valves 

 nearly equally elevated,, that of the ventral valve pointed ; area 

 very small ; foramen large. Surface tinely striated ; strise fre- 

 quently bifurcating and curving towards the lateral and cardinal 

 margins, concentrically marked by finer stride and stronger lines 

 of growth, which are numerous in the older shell. 



Locality. Helderberg mountains. 



Oe-this oblata. 



