334 



THE GEOLOGY OE MAIDSTONE. 

 By W. H. Bensted, Esq. 



{Continued from 2)age 2>^\.) 



The Kentish Eagstone is a source of very considerable trade to 

 Maidstone, and gives employment to many workmen. Several barges 

 are constantly engaged in conveying to the coasts of Kent and Sussex, 

 in the marshes of which it is very extensively employed for the banks 

 or sea-walls. In Homney Marsh and on the eastern side of the Isle 

 of Sheppey a large expenditure is yearly incurred in thus protecting 

 large and valuable tracts of land from the ravages of the sea. The rag- 

 stone is also extensively used as a road-stone and for buildings, large 

 quantities of the stone being sent to London and other places espe- 

 cially for the former purpose. A small quantity is burnt into lime of 

 a very superior quality ; but the abundance of chalk in this neighbour- 

 hood, and the greater cheapness of that rock, prevents the general use 

 of the stronger but more costly stone-lime. 



Many handsome buildings in Maidstone and other places in the 

 county are built of it. Of these in Maidstone may be mentioned 

 the new gaol, the lunatic asylum, and the new church. Of ancient 

 buildings constructed of it are the old parish church of All Saints, 

 the Episcopal Palace and College. Many of the London churches, and 

 nearly all of those on the banks of the Thames and Medway, have a 

 great proportion of this stone in their walls ; and proofs of its dura- 

 bility and early application to building purposes may be seen in the 

 present condition of AUington and Rochester castles, and most of 

 the bridges from Aylesford to Tunbridge. 



In removing the pier of the centre arch at Aylesford, the mortar, 

 made of ragstone-lime, had become so hard that blasting by gun- 

 powder was necessary to separate the stones. 



In the Iguauodon quarry alone from twenty-five to thirty men are 

 constantly at work. Upon uncovering the stone, the surface and 

 sides are found to be water-worn in an extraordinary manner; the 

 cause of which will be considered when the superficial clay is de- 

 scribed. The upper layer is very irregular in thickness, and is of an 

 ^ - r , inferior quality, beings porous and cherty, of a 



spongeous structure, and coloured by oxide of 

 ;# iroii. The principal fossil is Trigonia spinosa, 

 % which occurs in chalcedony. These trigoniseare 



frequently met dispersed over the surface-soil, 

 ^ , being the relics of beds of stone which have been 



IS ^ ^ ' subjected to destruction. This layer is about 6 



to 8 inches thick, and of a concretionary cha- 

 Fig._ 7.— Alcyonium (?) meter. A group of three lavers of stone follow 

 from upper beds. ^ ^^^^^ . ^^^^^^ i^^-^^^ j^.^^;^^ crystalline, and 

 sliglitlv tinge d of a ferruginous colour. The upper layer, contains 

 quantities of the stems and lobes of a singular sponge or zoophyte, in 



