Part of Gloucestershire and Somersetshire. 341 



in the immediate environs of Tortworth^ we find the sandstone alternating- 

 with limestone^ and the two supporting the coal formation ; but the immediate 

 base of this last formation consists of a broad belt of sandstone and sand- 

 stone conglomerate. 



What may be termed the fundamental portion of the old red sandstone, is 

 best displayed in Milbury heath and Tortworth hill. In general character 

 it accords with the sandstone of the banks of the Severn ; but in the higher 

 beds, yellowish and grayish strata prevail, sometimes containing interstices 

 filled with iron ochre ; while clayey or marly beds are comparatively rare, and 

 of smaller dimensions. In some of the upper strata may occasionally be 

 observed a laminated structure, the laminae forming oblique angles with the 

 planes of stratification, a disposition that has been sometimes also remarked in 

 other rocks. On the other hand, in the lower portion of the formation, there 

 occurs a considerable body of sandstone conglomerate, which may be traced 

 from the north-western foot of Milbury heath to Highwood in the vale of 

 Falfield, and thence around the northern foot of Tortworth hill nearly to Tort- 

 worth church. The conglomerate consists of rounded and angular fragments, 

 some being as large as turkey's eggs, of yellowish, whitish, and reddisli 

 quartz, with smaller pieces of slate, compacted by a base of granular quartz, 

 — in which are scattered some portions of indurated clay, and particles of 

 felspar mostly in a decayed or earthy state, and also a few scales of mica. 

 The base of the conglomerate is partly of a grayish, partly of a reddish cast ; 

 the rock is commonly disposed in beds, varying from 2 feet to 6 feet in thick- 

 ness, divided by other beds of firm fine grained sandstone, or red perishable 

 micaceous sandstone, two feet thick ; which last contain thin layers of con- 

 glomerate. 



Pursuing the curved line, formed by the course of the old red sandstone, 

 from the head of the Falfield valley to the vicinity of Wickwar, we find the 

 strata inclined 



At the north-western foot of Milbury heath, 45° (o the N.W. 



At the northern brow of ditto, .10° W. 30° S 



At the south-eastern side of ditto, where the ^ 



sandstone supports the limestone in a con- >20° S. 20° E. 

 formable position, . .... J 



In the vale of Falfield and north-western part of ") ,,,.0 o uxo p 



Tortworth park and hill, .... J 

 In the north-eastern brow of Tortworth hill 



the lower beds, ..... 20° 



the upper beds, .... 10' 



^|s. 35^- W 



