238 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Nov. 18, 



Isastrsea. Pecten laevis, &c. 



Cidaris. Belemnites abbreviatus. 



Nucleolites. Ammonites catena. 



Clypeus. perarmatus. 



Lima. Chemnitzia. 



Ostrea gregaria. Turbo, &c. 



The top of the rock is waterworn. 



D. Kimmeridge Clay. Here only about 100 feet thick. At its 

 base are scattered a few Coprolites ; a few feet upward we find 

 Thracia depressa, Gryphcea virgula ; still higher, two " flats " of 

 Ostrea deltoidea ; and at a height of 15 feet a limestone-band, 

 partly septariate, yielding Rhynchonella inconstans, and occasion- 

 ally Pliosaurian, Ichthyosaurian, and Steneosaurian bones, which 

 also occur below it. 



E. The Portland Sands, with included rock-bands and hard nodules, 

 rich in shells, 70 or 80 feet. The most cemented masses of rock 

 in the lower part have been quarried. The uppermost part is 

 green sand ; and small grains of silicate of iron are scattered 

 through the whole of the rock. There is an included bed of clay, 

 3 feet thick. Fossils of the Portland series are traced through the 

 whole, even up to the top, such as — 



Ostrea expansa. Cardium dissimile. 



Trigonia gibbosa. Pecten lamellosus. 



Astarte cuneata. Perna. 



Pholadomya. Nerinsea. 



Trochus giganteus. Terebra portlandica. 



Turritella excavata. Natica elegans. 



Ammonites triplex. Buccinum naticoideum. 



(No Belemnite is seen.) angulatum. 



F. Iron-sand-and-Ochre-series to the top of the hill, 80 feet. The 

 whole consists of yellow and white sands, varied with brown and 

 even black colour, — sandstones, sometimes cherty; — nodular and 

 geodic formations of oxide of iron, — bands of white clay, — and 

 local accumulations of ochre. Mr. Conybeare presents the follow- 

 ing section * : — 



Beds of highly ferruginous grit, forming the summit of the hill ... 6 feet. 



Grey sand 3 



Ferruginous concretions 1 



Yellow sand * 6 



Cream-coloured loam 4 



Ochre 6 in. 



Clay "1 thickness 



Ochre J not given. 



Ferruginous sands, cherty and argillaceous loams of a deep cream- 

 colour 40 feet. 



Thus above 60 feet are assigned to the group of Iron-sands. It 

 is in the lower group, which also contains ochre, that the shells 

 occur which were first noticed by Mr. Jelly. He found them about 

 30 feet above the Portland Rocks ; but my observations lead to the 

 conclusion that they occur in all parts of the deposit, from the very 



* Geol. of England, p. 139. 



