176 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 30, 



ft. in. 

 1 a. Stiff laminated light blue shale (with 7 or 8 cream-coloured 

 indurated veins ; the lower courses nodular and from 1 ^ 

 to 4^ inches thick, containing Insects), with layers of 

 Cy prides, also Cy eludes and a few PaludincB 3 9 J 



Blue and light brown, stiff, sandy shale, occasionally much 



indurated, containing CycZflc/es? — in masses 4 



Bluish-grey shale, less compact than the above (12 to 15 



inches) 1 



Layers of yellowish-brown shale, very irregular in thickness, 



perhaps from 8 to 12 inches 9 



Compact sandy ferruginous rock (the " ironstone " of the 

 workmen) stated to be 3 feet thick, but not well ex- 

 posed during our visit : the Grit for which the quaiTy 

 was worked, and of which a large quantity was collected 

 in stacks, was said also by them to l)e immediately below 

 this. 



2. On the Age of the Fossiliferous Sands and Gravels of 

 Farringdon and its Neighbourhood. By Daniel Sharpe, 

 Esq., F.II.S., F.G.S. &c. 



[Plates V. and VI.] 



Although the various maps and memoirs hitherto pubhshed, which 

 have included the neighbourhood of Farringdon, have all agreed in 

 classing with the Lower green sand the fossiliferous gravel full of the 

 remains of sponges, which lies on the south of that town, there has 

 been a suspicion in the minds of several palaeontologists that this 

 classification had been adopted on imperfect evidence, and that a 

 more careful examination might lead to a different result. As the 

 correct determination of this point seemed likely to throw light upon 

 other localities, I determined to spare no pains m collectmg and ex- 

 amining the organic remains upon which the decision must ulti- 

 mately rest. 



In justice to those whose views I am about to combat, I must con- 

 fess that I returned from my first ^isit to Farringdon, in the spring 

 of 1850, convinced that the Sponge-gravels belonged to the upper 

 part of the Lower green sand, the Terrain Aptien of M. d'Orbigny. 

 My first doubts on the subject arose from Mr. INIorris pointing out 

 to me how many of the Farringdon fossils agreed with those of the 

 Upper green sand of England, and of the Tonrtia of Belgium : this 

 led to a closer examination of the matter, which at last brought me to 

 the conclusion that the deposit, though belonging strictly to the cre- 

 taceous series, is a more modern member of that series than the Chalk. 



The Lower green sand is the only member of our cretaceous series 

 of marine origin, yet recognized, containing any large accumulation of 

 ferruginous sand or gravel. Ferruginous beds are very rare in the 

 Upper green sand, and are never fomid in the Gault or Chalk, hence all 

 ferruginous deposits containing any cretaceous fossils have been called 



