GEOLOGY 



in reptilian bones and teeth, belonging to the extinct genera Iguanodon^ 

 Hylceosaurus, Cetiosaurus, etc. 



During medieval times the ironstone was collected and smelted at 

 many places along the outcrop of the Wadhurst Clay in Kent, as well 

 as in the adjacent parts of Sussex and Surrey ; and this industry continued 

 so long as the forests of the Weald were sufficiently extensive to yield a 

 good supply of wood or charcoal for fuel. Traces of the old excavations 

 and of the slag-heaps where the stone was smelted are still visible in 

 many places, as for example on the rising ground between Tonbridge 

 and Penshurst. The fine ironwork railings which were round St. Paul's 

 in London until about thirty years ago were wrought at Lamberhurst on 

 the Kentish border. In the year 1740 there were still four furnaces in 

 Kent, but these had fallen into desuetude before 1788.^ 



Tunbridge Wells Sand. — This term is applied to the uppermost sub- 

 division of the Hastings Beds, from the district where it is widely 

 developed. The Tunbridge Wells Sand does not diffisr much from 

 the Ashdown Sand in general character, its material varying from a fine 

 loamy semicoherent sand, with intercalations of silt and mottled red clay, 

 to a soft thick-bedded sandstone, often with seams of small pebbles in the 

 upper part. In the latter condition it forms the picturesque rocks of 

 Rusthall Common and High Rocks near Tunbridge Wells. 



This subdivision occupies the greater part of the tract covered by 

 the Hastings Beds in Kent. It is occasionally sufficiently indurated to 

 be quarried as a building stone, and sandpits are numerous in its softer 

 beds. The soils derived from it are sometimes too ' light ' for profitable 

 tillage, and such tracts remain as uncultivated moorland or woodland ; 

 but more frequently there is a sufficient admixture of loam and clay to 

 produce fertile arable land at its outcrop. It rarely contains fossils other 

 than fragmentary traces of plants. Like the Ashdown Sand, it is generally 

 a water-bearing formation, the more porous sandy beds being the source 

 of numerous springs; but the water is liable to be slightly chalybeate, as 

 in the well-known springs at Tunbridge Wells. 



The Hastings Beds were evidently formed as sandbanks in a lake or 

 estuary by currents of considerable strength, with intervals of stiller water 

 in which the intercalated muds and clays were deposited. The sands are 

 very generally ' false-bedded,' i.e. the original stratification of the com- 

 ponent layers has not been horizontal, but has accorded with the slope 

 of the more or less steeply inclined banks into which the sediments 

 were driven. Consequently it is not surprising to find that although 

 the total thickness of the series in southern Kent and Sussex, where the 

 greater part of the material was deposited, exceeds 600-700 feet, it has 

 been proved by the deep borings to thin away very rapidly northward 

 and north-eastward, and is entirely absent in the northern part of the 

 county. 



The river-system which transported the sediments forming the 

 Hastings Beds has usually been supposed to have flowed from a land 



' ' Geology of the Weald,' p. 331. 

 7 



