lii PROCEEDINGS OP THE GEOLOGICAL SOCIETY. 



though it may scarcely seem consistent with the passage above quoted 

 from his memoir, in which he might appear to exclude the water 

 which was necessary as an agent of transport. 



Mr. Martin has published in the Philosophical Magazine during 

 the last year, an account of the phaenomena of elevation and denuda- 

 tion of the district of the Wealden, which has since been printed in a 

 separate form under the title " On the Anticlinal Line of the London 

 and Hampshire Basins." The principal part of it was embodied in a 

 memoir read before this Society Dec. 16, 1840, and which only failed 

 by some accident to be published in our regular Proceedings. I rejoice 

 that the author has repaired the loss to geology by thus printing his 

 memoir. The value of local and detailed observations from so care- 

 ful an observer, intimately acquainted with the district, cannot be too 

 highly appreciated. In this paper Mr. Martin has described the 

 Drift of the same district as that to which Sir R. Murchison's descrip- 

 tion applies. He separates it into four separate zones, as follows :— 



f Pebbles and broken shingle beds ; slight ad- 



1. Tertiary zone < mixture of angular flints; sand and loam, 



L and some chalk-rubble. 



rt p , / Angular flints ; pebbles very rare ; very little 



^. v^retaceous zone ...si -i. ,• iin iii 



I loam, but sometimes much chalk-rubble. 



rt « 1 - r Angular flints with chert, ironstone, and 



Subcretaceous zone | ^^„^t„„g . ^^^^ sand and little loam 

 4. Wealden zone 



riron rag (a conglomerate of the debris of the 

 J various beds above and below the "Weald 

 ] Clay). Beds of diluvial loam, sometimes of 

 [_great depth. 



The first two contain bones of mammals, and other Pleistocene 

 remains ; the third contains very few, and the fourth scarcely any 

 at all. 



This description is very similar to that given by Sir R. Murchison, 

 though difl'erently arranged. The first zone probably includes a 

 somewhat wider range than that contemplated by the latter author, 

 and therefore perhaps includes more of the tertiary pebbles. Sir 

 Roderick has stated that there is a marked absence of flints over the 

 surfaces of the Upper Greensand and Gault, especially along the foot 

 of the escarpment of the South Downs. Mr. Martin has not recog- 

 nized this fact. The tract would divide his Cretaceous and Subcreta- 

 ceous zones. In the Wealden zone he seems to have recognized a 

 greater extent of detrital matter than other geologists, in the exist- 

 ance of considerable beds of diluvial loam. 



Mr. Martin's views respecting the general structure of the district 

 are, in all essential points, in perfect accordance with my own, as 

 brought before the Society some years ago. I was, in fact, indebted 

 to him for most of the details of the phaenomena in his own im- 

 mediate neighbourhood ; and a considerable portion of the contents 

 of his present essay would have appeared in conjunction with my 

 memoir, had it not been for the accidental omission already alluded 



