112 Miss Eyton — Neiver Deposits of North Shropshire. 



ttey are blackened by an impregnation of lignite. I have already 

 mentioned the doubtful example at Leaton. 



Occasionally, but very rarely, mammalian remains occur in these 

 beds. I am indebted to Mr. Blunt, of Shrewsbury, for two teeth of 

 an ox, found in gravel in the Abbey Foregate, Shrewsbury, and 

 a horse's tooth, perfectly blackened with age, was found in sand in 

 digging the foundation of a bridge between the villages of Bratton 

 and Eyton, near Wellington. 



There appear to have been two distinct periods of denudation in 

 Shropshire during the formation of this whole series of beds. First, 

 the denudation of the Lias ; and secondly, that of the Triassic con- 

 glomerate. The former of these must have been effected by a cur- 

 rent from the north, bearing with it northern materials, granite, etc. 

 Indeed, its course across the plain of Cheshire seems well marked by 

 the clays, sands, and gravels which it deposited. Crossing the Lias, 

 of which the remains still exist on the Shropshire and Cheshire 

 border, overlying the Keuper Marls, it proceeded southward across 

 the plain of North Shropshire, leaving its traces in the deposits, from 

 the Blue Clay, upwards, to the sandy gravels, behind it. 



The Silurian ridges of South Shropshire seem to have acted as a 

 check to its progress, which was diverted to the south-east, whence 

 it proceeded down " the ancient Straits of Malvern " (weakened, 

 however, in force, and bearing a very diminished number of recog- 

 nizable species of shells) into the Irish Sea. This, at least, was Sir 

 Eoderick Murchison's opinion, and there scarcely seems sufficient 

 reason, in any of the modern discoveries, much as they have in- 

 creased our general knowledge of these beds, to weaken its force. 

 While, therefore, we thankfully accept a position for our ancient sea- 

 beaches on the horizon of the Middle Drift, we cannot yet give up 

 our right to their old title, bestowed upon them by the father of 

 Shropshire Geology, that of " Northern Drift." 



The denudation of the Triassic conglomerate took place, as we 

 have seen, at a later period and under different auspices. The 

 reasons which render it doubtful whether this could have been the 

 effect of marine agency, have been already stated, while on the other 

 hand the very large amount of material removed (for this bed, like 

 the Lias, remains a mere wreck of what it has been), and its even 

 distribution over the plain, show it to have been the work of far 

 more powerful and widely-spread forces than any now in action ; and 

 again, as the materials of these re-assorted drifts are all derived 

 from local sources, the presumption is that they owe their origin to 

 local agents. 



Between these two periods, one apparently of general, the other 

 of local denudation, there was an interval of which we have in 

 Shropshire no traces— that of the later Boulder-Clay. I am not 

 aware of any instance in which the marine drift is overlain by clay, 

 nor have we any beds in any part of North Shropshire that can be 

 assigned to this formation. It is difficult, sometimes it seems well 

 nigh impossible, to correlate any series of beds with those corres- 

 ponding to them in another series, known only by description, how- 



