270 



CRETACEOUS LAMELLIBRANCHTA. 



I'JOG. Inoceramus sulcatus, ^4. WoUcmann. Jahrlj. J. k. pruuss. geol. Landesanst. 



fiir 1906, vol. xxvii, p. 273, pi. vi, 

 %. 10. 



Noil 1827. 



S. Nilsson. Petrif. Suecana, p. 18. 



Dcscrlpliou. — Shell more or le.ss ovate, mucli liiglier than long, very inequi- 

 lateral, more or less considerably inequivalve. Anterior j^art of valves flattened 



Fia. 30. — Inoceramus, s^. Gault, Folkestone. Sedgwick Museum, Cambridye. Internal ciist nf liylit 



valve. X ^. 



or concave. Posterior part somewhat expanded and loss convex than the part 

 below the umbones. Left valve very convex, with a liigh, narrow, pointed 

 anterior umbo which is considerably incurved and bends forwards. Right valve 

 rather less convex than the left valve, with a smaller umbo whicli bends forwards 

 and slightly inwards. 



Ornamentation consists of strong angular radial ridges ([)lications), usually 

 from eight to ten on each valve, which are often unequal in size and are separated 



