36 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 9, 



the Etage Cenomanicn of the French geologists, and is approximately 

 equivalent to the Greensand of Blackdown. 



4. The Zone of Ostrea carinata represents most certainly a portion 

 of the Upper Greensand of England and the Lower Cenomanien of 

 Normandy. 



5. The Chloritic Sands and Sandstones have, on the whole, a fauna 

 possessing an Upper Greensand facies, many species, however, pointing 

 to higher zones. 



It is very probable that the Chloritic Sands of Woodburn (the 

 " Zone oi Inoceramus Crispi'i") may be inferior to the Chloritic Sand- 

 stones of Colin Glen— the " Zone of Exogyra cohanbaJ' These two 

 zones, however, never come in contact. 



6. The Upper Chalk contains three subdivisions : — - 



a. Zone of Ananchytes gibhtis. 

 h. Spongarian Zone. 



c. White Limestone, or the Zone of Ammonites GoUevillensis. 

 The White Limestone certainly represents the Upper 

 Chalk of Norwich and the ' Craie de Meudon '; and some 

 of its fossils point even to a higher parallel — rthat of 

 the Maestricht Chalk. 

 These conclusions are represented in the comparative Table of the 

 Upper Cretaceous formations at pp. 34 & 35. 



YIII. Desceipttons of Species. 

 1. Ammonites occlusus, spec. nov. PI. III. figs. Irt, 16. 



Shell inflated, with obscure ribs, which are continued over the 

 rounded back ; umbilicus imperforate, impressed. Outer whorl em- 

 bracing all the others, slightly compressed, and gradually increasing 

 so as to form a wide elliptical dilated aperture. 



Dimensions. — Diameter Ij'y inch ; diameter of outer whorl 1 inch ; 

 median thickness of outer whorl -^^ inch. 



Affinities and Differences. — In the disposition of the lobes and 

 saddles of this species, A. occlusus bears a great resemblance to A. 

 GoUevillensis, D'Orb., A. Gldliami, Sharpe, A. Letvesiensis, Sow., and 

 A. eolligatus, Binkhorst ; but it cannot be regarded as the young of 

 any of these, for in them the umbilicus is open and not imperfo- 

 rate. In its general form, impressed and imperforate umbilicus, and 

 in the general character of its sutural markings, it is closely related 

 to the species constituting the section HeteropJiylli ; among the 

 Cretaceous species it has affinities with A. Rouyanus, D'Orb,, A. 

 Forbesianus, D'Orb. (A. Rouyanus, D'Orb., Forbes), and A.pic- 

 turatus, D'Orb. From A. picfuratus it is at once distinguished 

 by its more angular sutural lobes. The nearest known ally is A. 

 Forbesianus. I have compared A. occlusus with the Indian species in 

 the coUeetion of the Geological Society, and the general facies of the 

 two are most certainly different. In A. Forbesiamis the back is 

 more inflated, and the sides slope gradually down to the imperforated 

 umbilicus. In A. occlusus the last whorl is not so convex, is some- 

 what flattened from side to side, and the imperforate umbilicus is 



