1853.] SHARPE SANDS AND GRAVELS OF FARRINGDON. 1/9 





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of the Sponge-gravels is seen in the village 

 of Fernham, where it has been quarried in 

 a pit now abandoned. Although ill-exposed, 

 enough may be seen of it to show that it 

 agrees in mineral character and organic 

 contents with the deposit at Little Coxwell. 

 The junction of this mass with the Lower 

 green sands of the Furze Hills is not vi- 

 sible. The Lower green sand being thus 

 flanked both to the north and south by a 

 mass of the Sponge-gravels, it hardly admits 

 a doubt that it is the older deposit of the 

 two, for there is no difficulty in supposing 

 the Sponge-gravel thrown up against the 

 sides of the pre-existing hill of Lower green 

 sand ; but it would have required a most 

 complicated process of denudation and de- 

 position to have lodged the Lower green 

 sand in the hollow between the two masses 

 of the Sponge -gravel. 



The annexed section, altered from that 

 published by Mr. Austen*, explains the 

 views above stated. 



Having thus exhausted the assistance to 

 be derived from their position, we are ne- 

 cessarily reduced to internal evidence as the 

 only means of fixing the age of the gravels 

 of Little Coxwell. The pebbles found in 

 them are mostly of two classes ; either 

 lumps of an earthy limestone, frequently 

 pierced by boring shells, derived no doubt 

 from one of the oolite formations ; or small, 

 well-rounded, siliceous pebbles of various 

 kinds, as quartz, jasper, hornstone, and 

 some closely resembling chalk-flints ; but 

 notwithstanding a good deal of search, I 

 was unable to find any pebble which could 

 he pronounced with certainty to be formed 

 of flint from the Chalk. We are thus 

 thrown entirely on the organic remains for 

 assistance. In examining these, we must 

 first separate all those which appear to have 

 been washed out of older rocks, and brought 

 to the spot already mineralized ; these are 

 very numerous, and for the most part they 

 are readily recognized by their appearance 

 and mineral condition : they are derived 

 principally from the (-oral rag and Kim- 



* Quart. Journ. Geol. Soc. vol. vi. p. iCtZ. 



