728 GEOLOGY. 



Wealden Group. The deposits under this name, generally associated with oolitic strata 



by British geologists, occur principally in the wealds or wolds of Kent and Sussex, a 

 tract covered with extensive forests in former times, and hence so denominated from 

 the Saxon wald, a wood. Caxton, the first English printer, in the first book ever 

 printed in the native language, remarks, that he was " born and learned mine English 

 in Kent in the weald," a district now rich corn land and pasture, traversed by a railroad, 

 which he describes as then "a desert and waste wilderness, stored and stuffed with 

 herds of deer and droves of hogs." The country in question is bounded by the chalk 

 hills of the North and South Downs, with the green sand of that formation at their base, 

 and by the sea for some miles on each side of Hastings. Its greatest extent is nearly 

 sixty miles from east to west, and about twenty miles from north to south ; but analogous 

 accumulations to those of the weald appear on the opposite coast of France, near Boulogne 

 and Beauvais, and detached portions occur as outliers in the peninsulas of Purbeck and 

 Portland, and in the Isle of Wight. 



The Wealden formation consists of ferruginous sands and sandstones, which extend 

 from Hastings to Tonbridge on the north, and to Horsham on the west. Beyond this 

 area a zone of blue or brown tenacious clay appears at the surface, sometimes indurated 

 and slaty. This zone is the most important member of the group, for it not only circles 

 round the central deposit, but underlies it, and crops out in the lofty cliffs on the coast. 

 The central region, or nucleus of the weald, is elevated, Crowborough beacon attaining 

 the height of more than 800 feet, but the surrounding clay constitutes a flat track, having 

 an average breadth of about five miles. Thin beds of limestone occur in the clay, 

 separated by argillaceous seams, almost wholly composed of paludinse, the shells of a 

 species of snail, held together by crystallised carbonate of lime. This limestone, when 

 polished, forms the well-known Sussex marble so extensively employed by the archi- 

 tects of the middle ages for decorative purposes. The columns, pavements, and monu- 

 ments in our cathedrals and ancient churches are often composed of it, or of the 

 Purbeck marble, a limestone of the same age and, group, but an aggregation of a smaller 

 species of the same shells. A row of columns in Chichester cathedral, and those of the 

 Temple church in London, the tomb of Queen Eleanor in Westminster Abbey, and 

 the throne of the Archbishop in Canterbury Cathedral, are constructed of this material ; 

 the fragile shells of humble snails ; once familiar with slime and mud ; which have 

 been petrified and agglutinated into an enduring limestone by the mysterious chemistry 

 of nature, and subsequently converted into polished marble by the art of man ! But its 

 use in architecture appears to go back to the era of Roman domination in Britain. In 

 the year 1723 a slab of grey Sussex marble was dug up at Chichester, bearing an 

 inscription recording the dedication of a temple: "The college, or company of arti- 

 ficers, and they who preside over sacred rites, or hold offices there, by the authority of 

 King Cogidubnus, the legate of Tiberius Claudius Augustus, in Britain, dedicated 

 this temple to Neptune and Minerva, for the welfare of the imperial family ; Puderis, 

 the son of Pudentinus, having given the site." This interesting relic of the olden time 

 is now in the grounds of the Duke of Richmond at Goodwood. 



There are no deposits of greater interest than those of the weald, on account of the 

 striking forms of organic life unfolded by them> and the remarkable changes they pro- 

 claim to have occurred in this locality. The chalk in the hills of the North and South 

 Downs has been mentioned as forming its general boundary, except where it is open to 

 the sea ; and as the wealden beds emerge from beneath the surrounding chalk, the pro- 

 bability is, that it was once continuous over them, and has been swept away from the 

 enclosed area by some great denudation. However this may be, it is certain that while 

 the chalk, under which the wealden strata dip, and the upper beds of oolite upon which 



