50 



BASE OF NEW RED SYSTEM, GLOUCESTERSHIRE. 



describes these shelly marls as lying between the formation No. 2. of the last chapter, 

 and the Lower Red Sandstone, and consisting of red-coloured marls, with thin-bedded, 

 yellow or reddish mottled limestone, both concretionary and granular. " I view them," 

 he adds, " as attenuated and deteriorated magnesian limestone, the last term of the 

 degradation of this rock." From the observations, therefore, of Professors Sedgwick 

 and Phillips, there can be no doubt, that the Manchester shelly beds are of the same age 

 as the calcareous and dolomitic conglomerates of Salop, Worcester and Stafford, which 

 are the equivalents of the Magnesian Limestone. 



These marls must be regarded with great interest, as links connecting those peculiar 

 types of the lower New Red Sandstone described in the concluding part of this chapter, 

 with strata of the same age in the North of England, which are known to geologists 

 through the labours of Professor Sedgwick. Among the shells from the marls at Col- 

 lyhurst, Professor Phillips recognises Axinus obscurus, M. C, or a large variety of that 

 species, as the most prevalent, associated with an Avicula, not very remote from A. socialis 

 of Schlotheim; and many small undescribed univalves. The same author holds out 

 the prospect of publishing a monograph of the fossils of the magnesian limestone, 

 including all the species in the Manchester marls. 



Having now described the three upper divisions of the series in those districts, where 

 their characters and order of superposition are distinct, I might at once proceed to the 

 examination of the subjacent sandstones, where they are most expanded, as around the 

 coal-fields of the central counties. It is desirable, however, previously to invite atten- 

 tion, to the prevailing characters of the lower portions of the system, in Gloucestershire 

 and the West of Worcestershire, where the system being little developed, the whole of 

 its lower portion, consisting of conglomerates and sandstone, is so intimately connected, 

 that it can be considered only under one head. 



Base of the New Red System in Gloucestershire and south-western parts of Worcestershire. 



In Gloucestershire and the adjacent part of Worcestershire, the members which con- 

 stitute the bottom of the system, are sandstones and conglomerates of mixed characters, 

 sometimes slightly calcareous, at others quartzose, and occasionally containing great 

 abundance of pebbles and fragments of trap rock, intermixed with sedimentary rocks 

 of high antiquity. Such beds may represent either the central Sandstones and Quartzose 

 Conglomerate No. 2, or the Calcareous Conglomerate No. 3, or the Lower New Red 

 Sandstone No. 4. 



This view is rendered probable, by the gradual expansion of the respective members of 

 these deposits in their range from south to north, until they attain that great development, 

 which constitutes the New Red System of the northern parts of Worcestershire, Stafford- 

 shire and Shropshire. Having personally traced the line of demarcation between these 



