and the adjoining Parts of Hants and Surrey. 103 



of it is seen to the east, for 7 or 8 miles, than a narrow gorge, which is flanked, 

 on the north, by the lofty hills of Blackdown, and on the south, by the corre- 

 sponding ridge extending from Holder and Bexley hills to near Petworth. 

 The valley is then suddenly expanded to three times its former breadth by the 

 retirement at a right angle of the sand-escarpment of Blackdown and Hasle- 

 mere. 



In the extensive vale thus laid open the best specimens of the- Sussex or 

 Petworth marble are found. The disintegrated beds near the surface afford 

 the characteristic Viviparse in abundance, whilst in the more compact masses 

 the Ci/pris Faba may also be discovered. The different localities of this marble 

 are given in the annexed table of the order of superposition : but it may be 

 remarked that the parish of Kirdford contains some of the largest and finest 

 slabs. 



Iron-ore is much disseminated through this formation, as well as through 

 the inferior formation of Hastings or Iron Sand. — The Weald clay abounds 

 in ancient iron-works, and their sites are still to be traced from near the 

 junction of the lowest beds with the Hastings sand, up to the highest beds at 

 the base of the lower green-sand. In the gorge of Harting Combe, at Lynch, 

 Redford, &c. &c., the slag of the extinct furnaces is yet used as a material for 

 repairing roads. These places are situated from 10 to 12 miles west of the 

 outcrop of the iron-sand. 



V. Hastings or Iron Sand. 



This lowest formation of the vale of Sussex rises in gentle undulations im- 

 mediately to the east of Kirdford in the parish of Wisborough Green, where, 

 at Headfold-wood Common near Loxwood, its outline makes an angle, cor- 

 responding to that formed by the Weald clay and the superior strata. 



Although these beds at their first emergence consist chiefly of clay, yet 

 they differ essentially from the Weald clay in containing near the surface small 

 flags of a slightly calcareous sand-stone, and beneath these, large tabular 

 masses of a calcareous grit, which is very similar to certain beds of the Stam- 

 merham and Slinfold quarries west of Horsham. Unlike, however, to the latter, 

 the calcareous grit-stone of Wisborough Green is based upon a deep mass of 

 red ferruginous marly clay, and is only found in detached portions. 



The Horsham beds have already been wefl described by Mr. Lyell, in a letter 

 addressed to Mr. Mantell and read at the Geological Society, and have been 

 examined by Mr. L. atStammerham; but their extension to Skiff Common and 

 Loxwood, from 9 to 10 miles west of that place, has not previously been noticed. 



I have now the satisfaction of laying before the Society numerous fossil 

 remains of large vertebrated animals from two localities at the extreme 



