Dr. PiTTON on the Strata below the Chalk. 



137 



SURREY. 



(45.) Godstone. — The upper green-sand assumes a new character near 

 Godstone ; and a step-like projection at the foot of the chalk appears there 

 more distinctly than in the country to the east. As the productions of 

 the little district between Godstone and Reigate are valuable in commerce, 

 and its structure has been a subject of some doubt^ I have given a separate 

 map of it, in Plate VII. fig. 2.* The section, Plate X. a.. No. 2., on the 

 line from the chalk through Godstone, shows the position of the firestone 

 beds in the upper green-sand ; with the site of a remarkable elevation of 

 the strata at Tilburstow Hill, an account of which has been already published 

 by Mr. Mantellf : and No. 3., the section through Merstham, includes the 

 site of the Fuller's-earth pits of Nutfield. 



(46.) The firestone subordinate to the upper green-sand, in this part of 

 the country, was, in 1827, extracted only between Godstone and the west of 

 Reigate. The principal pits were situated on the west of the London road 

 to the former place. The stone was obtained by an adit between five and 

 six feet in height, and the succession of the beds affording it was thus : 



Section of one of the Firestone Pits near Godstone. 



Feet. In. 



1. ^^ Hard roof ." This, like the firestone beneath, is a uniform fine-grained con-' 

 glomerate or sandstone, effervescing strongly with acids, and easily cut into 

 any desired form. Throughout the stone are dispersed numerous minute I 

 scales of mica, and dark particles, scarcely perceptible without a lens. It 

 forms a roof to the mines, of such firmness as to support itself to a width of 

 17 feet, extending indefinitely inwards. 

 "Green bed" of the workmen. {Firestone.) Stone of the same nature as the last, 

 but harder and somewhat finer in grain, easily broken down into sand, effer- 

 vescing. The beds 2. 3. and 4. though separated by seams of stratifica- 

 tion, are of nearly uniform character. 



5. A bed of bluish grey siliceous concretions, called "flints" by the workmen, pass-" 



ing into stone like that above mentioned. Fracture flat-conchoidal. Yielding 

 with great difficulty to the knife ; but effervescing slightly. The greyer stone 

 near these concretions is much harder than elsewhere. The siliceous )■ 

 matter as it becomes more pure acquires greater hardness, with a splintery 

 fracture and a glimmering lustre ; and the micaceous particles, which are 

 numerous in the softer varieties, are then scarcely apparent. 



6. " Green bed ;" — like 2. 3. and 4. j 



9 



4 

 10 



to 



4 



10 



In the small maps of this Plate the inequalities of the surface are not expressed: but the 

 colours can easily be transferred to the Ordnance map. f " Fossils of Tilgate," &c., p. 22. 



X The more uniform and softer rock of these pits is used, principally, for lining fire-places 

 VOL. IV. SECOND SERIES. T 



