100 PEOCEEDIIfGS OF THE GEOLOGICAI SOCIETY. [DoC. 21, 1870. 



observed in a summer ramble, from which, however, the following 

 general conclusions may be rawn. 



(1) That along the South Coast of England the Chalk Marl thins 

 westward from the Isle of Wight, where it is in good force, and its 

 bottom part becomes marked, in that direction, by the presence of 

 quartz-grains, mostly very small, but sometimes as large as a pea, 

 showing perhaps signs of a less deep-sea character than usual in 

 the deposit. This bottom bed is the most constant part westward, 

 where, indeed, it seems sometimes to be all that represents the Chalk 

 Marl. 



(2) That along the South Coast the Lower Chalk, of no very 

 great thickness in the Isle of Wight (about 200 feet perhaps), thins 

 westward until in Devonshire it is but 30 feet thick, and occasion- 

 ally less. 



(3) The consequent nearness of the Upper Chalk (with flints) to 

 the Greensand helps to explain the occurrence of the great deposits 

 of flints on the hills of the latter in Devonshire. 



Dtsctjssioit. 



Mr. Etheeidge pointed out the resemblance between the series 

 described by the author and that of the Chalk of Antrim. He 

 thought it probable that the Cretaceous beds had originally ex- 

 tended over the whole of Western England. He called attention 

 to the Blackdown beds, which had been regarded as Upper Green - 

 sand, but certainly were not so, though probably Cretaceous, as well 

 worthy of examination. 



Mr. Hull hoped that some Fellows of the Geological Society 

 would extend their examination of the Chalk into Ireland, and visit 

 the Antrim district. It was the case there that the Chalk with flints 

 rested immediately on the Upper Greensand, though there was an 

 intermediate band known as the Mulatto-bed, which might possibly 

 represent the Chalk-rock. 



Prof. MoEEis thought the paper afforded evidence in favour of the 

 Chalk having been deposited in a sinking area, and during the pro- 

 cess various alterations in the conditions took place. 



Mr. D. EoEBES inquired as to the character of the nodules men- 

 tioned, and whether they were siliceous or not. 



Mr. Meter mentioned that near Branscombe there occurred a band 

 within 8 feet of the Red Marl, containing fossils apparently the same 

 as those of Blackdown. 



Mr. Whitaker h3,d pui'posely avoided characterizing the greater 

 part of the Greensand-beds as either Upper or Lower. He thought 

 the cherty beds of the west were stratigraphically higher than 

 those of the Isle of Wight. The nodules inquired about were not 

 siliceous, though probably containing some silica, but were rather 

 phosphatic. 



