250 FORMATIONS ABOVE THE CHALK. 



Green Sand*. Crate Inferieur of the French. 



Large proportion of the S.E. of England. Quader sandstien, and Planer Kalk, of Wer- 

 ner. Younger Alpine limestone of Savoy, 

 forming the summit of the high ridge from 

 Mount Varens in the vale, of the Arve, of Dia- 

 bleret, in the Rhone valley. 



In the preceding arrangement, the excavations or hollows in the chalk, 

 containing the tertiary formations, are termed basins ; and these are 

 farther distinguished by the names of their principal locahties : thus we 

 have the Paris, London, and Isle of Wight basins ; the two last men- 

 tioned, comprehend the whole of the tertiary beds that have been noticed 

 in England. 



According to the plan of the present work, the alluvial and diluvial 

 beds, will be hereafter described. The freshwater limestone does not 

 occur in this county; the Druid sandstone, Plastic clay, and London clay 

 are therefore the only members of the series that come under examination 

 in this section. 



The Druid sandstone occurs in the form of boulders, promiscuously 

 scattered over the surface, or imbedded in diluvial deposits. The Plastic 

 and London clay occupy a considerable extent of country, and form the 

 low maritime district of the south-western part of Sussex. These beds 

 are supposed by Mr. Webster to have belonged to the Isle of Wight 

 basin ; to obtain a clear idea of their geological relations, it will therefore 

 be necessary to take a brief view of the extent, and characters, of that 

 celebrated depression of the chalk. 



The district comprehended by the Isle of Wight basin, is about 100 

 miles in length, and at its greatest breadth does not exceed twenty miles. 

 The southern side is formed by the highly inclined chalk, extending from 

 the Culver CHffs, at the east end of the Isle of Wight, to White Nose, in 

 Dorsetshire, five miles west of Lulworth; the north side by the South 

 Downs, that pass from Beachy Head, to Dorchester, in Dorsetshire, The 



* Professor Buckland continues this arrangement down to the Greywacke, of the transi- 

 tion series. 



