98 Mr. R. I. MuRCHisoN on the North-western Extremity of Sussex, 



sections of the coast of the Isle of Wight *^ my object is to point out the iden- 

 tity of this extensive inland tract, in which all the members of the series, from 

 the chalk to the beds below the Weald clay, appear to be more largely and 

 uninterruptedly displayed than in any other part of England. It is the more 

 necessary to define accurately all the strata of this district, inasmuch as three 

 of the formations have been hitherto described to be one range of green-sand ; 

 whereas the upper green-sand is divided from the lower, throughout the 

 whole of this country, by a distinct and important breadth of Gault clay, of 

 which the royal forest of Alice Holt forms the north-eastern portion. 



The strata, therefore, the relations of which it is my object briefly to de- 

 scribe, commencing below the chalk in a descending series ; are^ 



1st. Firestone, or Upper Green-sand. 



2nd. Gault. 



3rd. Lower Green-sand. 



4th. Weald Clay. 



5th. Hastings or Iron Sand. 



I. Firestone, or Upper Green-sand. 



This formation, which lies immediately below the chalk, is provincially 

 termed Malm-rock, and is known by that name alone in the counties of Hants 

 and Sussex, throughout a range of 40 miles. Its geognostic position and 

 the fossils it contains, prove it to be geologically identical with the upper 

 green-sand or firestone of Merstham. The beds are nearly horizontal, or they 

 dip at only a slight angle towards the chalk. The whole formation is pecu- 

 liarly characterized by constituting terraces, which vary in breadth from a 

 quarter of a mile to two and three miles, and which generally correspond to 

 the sinuosities of the chalk hills. These terraces are covered by a tenacious 

 grayish-white soil, celebrated for its abundant production of wheat. Quarries 

 are to be seen in all the lanes which intersect this country ; and in many 

 places the sides of the roads, which by the rapid decomposition of the rock 

 are worn into deep hollows, present sections from 20 to 30 feet deep. The 

 harder beds are used for building ; and though the occurrence of firestone is 

 not frequent, still that variety is seen in some places, at Selborne for instance, 

 where it is employed in the construction of ovens. 



The upper beds are the most cretaceous; but these sometimes pass into a 

 grayish-blue compact limestone, which is of great thickness at Binsted and 



* See Annals of Philosophy, 1824, New Series, vol. viii. 



