WEALD, OR OAK TREE CLAY. 63 



§ Sussex or Petworth Marble. 



Syn. — " Marmor viridi-cinereum cochleis refertum." Da Costa's Nat. 

 Hist, of Fossils, p. 235, No. Ixxvii. 



" Marble from Petworth, Sussex." Woodward's Catalogue, vol. i. p. 20. 

 X. b. 60 *. 



This limestone is of various shades of bluish grey, mottled with 

 green, and ochraceous yeUow, and is composed of the remains of fresh 

 water univalves, formed by a calcareous cement into a beautiful compact 

 marble. It bears a high polish, and is elegantly marked by the sections of 

 the shells which it contains. The shells belong to the genus vivipara of 

 Montfort, {Helix vivipara, of Linn^,) and are supposed to resemble the 

 recent species of our rivers: their constituent substance is a white crystallized 

 carbonate of lime, and their cavities are commonly filled with the same sub- 

 stance, presenting a striking contrast to the dark ground of the marble. 

 In other varieties the substance of the shells is black, and their sections 

 appear on the surface in the form of numerous lines and spiral figures. 



The Sussex marble occurs in layers, from a few inches to a foot in 

 thickness, and these are commonly separated from each other by thin 

 seams of clay, or of coarse friable limestone. It is frequently found in 

 blocks or slabs, sufficiently large for sideboards, columns, or chimney- 

 pieces, and but few of the ancient residences of the Sussex gentry are 

 without them. There is historical proof of its having been known to the 

 Eomans, " and in the early Norman centuries it was much sought after, 

 and applied as the Purbeck marble was, when cut into small insulated 

 shafts of pillars, which were placed in the triforia, or upper arcades of 

 cathedral churches, as at Canterbury and Chichester. At the first men- 



* " Marble from Petworth, Sussex. The ground grey, with a cast of green. 'Tis very 

 thick set in all parts, with shells chiefly turbinated. Some of them seem to be of that sort of 

 river shell that Dr. Lister (Hisf. Cochlear. Aug. p. 13^5.) called Cochlea maxima, fiisca sive ni- 

 gricans,Jasciata. Several of the shells are filled with a white spar, which variegates and adds to 

 the beauty of the stone. This is of about the hardness of the white Genoese marble." An 

 Attempt towards a Natural History of the Fossils of England, by J. Woodward, M D. London, 

 1729, tome 1. p. 20. 



