LOWER LIAS. 



21 



of which six beds are used, and known by the names of "Top/'* " Black/' "Tile/ 5 "Poacher/' 

 "Peaver," and "Bottom." The Poacher is an irregular course appearing and disappearing- the 

 " Bottom " is the best stone, and is seven inches thick. The strata on the north-west end of the 

 hill dip east- south-east 6°, but where they crop out the inclination increases to 12° and 15°. On 

 the higher parts of the hill the dip is north-east, and in its east-north-eastern face there are quarries 

 twenty feet deep, where the dip is west-south-west. This outlier and the range of Lias by Bushley 

 are, for the most part, covered with drifted superficial matter, composed of red clay, or gravel and 

 sand, which generally conceals the subsoil in this part of Worcestershire. 



At Brockeridge Common, north of Tewkesbury, the same strata are very well exposed, the work- 

 men reckoning five principal calcareous beds, including one of Tilestone. These are overlaid by 

 hard layers, and underlaid by slaty clay, which towards the base becomes sandy, and finally passes 

 into the thin-bedded white sandstone to be described in the next chapter. The lower Lias of Brock- 

 eridge contains the characteristic fossils found at other places, viz. abundance of the small Modiolfe 

 and Ostreae, together with Ammonites Planorbis, Plagiostoma giganteum, and other fossils. The 

 ordinary dip is about 10° south-east and east-south-east ; but in one place the lowest bed rises up 

 at an angle of 25°. As the lower Lias occupies the highest ground in the environs of Tewkesbury, 

 it is there dignified by the title of the "hill rock" in contradistinction to the red marl, which is 

 usually in the lower ground. 



The same lithological and zoological characters are preserved along the straight ridge of the lower 

 Lias, extending from Brockeridge Common to Boughton Hill and Pirton. 



The continuation of the lower Lias from Pirton and Norton, near Worcester, into 

 Warwickshire has been carefully traced by Mr. Strickland, jun., for many miles, and the 

 boundaries have been laid down by him upon the Ordnance Map, including several 

 large promontories of Lias hitherto unnoticed. He has also discovered that the New 

 Red Sandstone has been protruded through the Lias along a line of fault near Crop- 

 thorn. It never was my intention to trace the course of the Lias into Warwickshire, 

 and I have attempted to describe its characters in the Vale of Gloucester and Worcester, 

 merely to point out the peculiarities of lithological structure and zoological contents, 

 where the lower members pass downwards into the New Red Sandstone 1 . 



Such are the deposits which may be observed in crossing the Vale of Gloucester and 

 Worcester from east to west. They are all rocks of sedimentary origin, and are made 

 up of a prodigious number of beds or layers, each formation possessing an individuality 

 of mineral character and organic remains ; and as we descend in the series, we find the 

 remains of animals differing from those which had been deposited in the beds of earlier 

 age. 



These submarine accumulations have, however, undergone great alterations since 

 the period of their original deposit, either by denudation during their rise from beneath 

 the sea, or by disintegration since they have been exposed to the atmosphere. They 

 have likewise been greatly affected by disturbing agents, some remarkable proofs of 



1 The curious and important subject of the origin of the Cheltenham and other mineral waters of the Vale of 

 the Severn, will he entered upon, as soon as we have described those rocks in which they take their rise. 



C 



