316 Geology of Wiltshire. 



This was accompanied by a map reduced from the Ordnance Map, 

 and coloured geologically, which Mr. Scrope very liberally presented 

 to the Society. This very satisfactory introduction to the geology 

 of the county, was followed by an account of the Bradford Clay, 

 in vol. vi., also by Mr. Cunnington. A valuable paper on the 

 Geology of the country traversed by the Berks and Hants, and 

 Marlborough Railwaj's, was contributed to vol. ix., by Thomas 

 Codrington, Esq., F.G.S. And an admirable paper, by Dr. 

 Blackmore, containing a lucid account of the " Drift " in the 

 neighbourhood of Salisbury, was published in the tenth volume. 

 This paper contains the results of many original observations on 

 a branch of the subject, which is at once the most important and 

 the most popular in modern geology. 



We now propose to begin with the lowest rock developed in 

 the count}', viz. : — 



The Lias. 



As remarked by Mr. Scrope, vol. v., p. 98, the Lias only occurs 

 and barely within the limits of this county, in the bottom of the 

 deep valley of Box, where it joins that of the Avon. The upper 

 beds only of the stratum are found there, and we are not aware 

 that any examination of them has ever been made. 



A full list of Liassic fossils is printed in the Memoir, pp. 6, 7, 8^ 9, 

 but it has not been thought necessary to reproduce it here. 



Inferior Oolite. 



This formation, marked in the map g^, introduces the Oolitic 

 series, named from the oolitic or egg-like form of the grains of 

 some of its lime-stones. The thickness of the Inferior Oolite at 

 Stroud is about 150 feet, or 110 feet less than at Leckhampton Hill, 

 near Cheltenham. The principal sections occur at Nailsworth in 

 quarries, and natural cliffs at Brimscomb, and in the deep cuttings 

 of the Great Western Railway in the Golden Valley. The In- 

 ferior Oolite frequently forms tabulated spurs bounded by abrupt 

 banks which are planted with beech trees and pines ; of such there 

 are good examples in Slaughterford Valley. 



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