T11F. I 'K KM IAN SYSTKM 331 



of dolomitic Silurian limestone like that which occurs in th 

 AMx-rlcy Hills, the other half consisting largely of Carboniferous 

 limestone and sandstone. In Staffordshire, especially near 

 Baggeridge on the west, and near Barr on the east side of the 

 coalfield, the majority of the pebbles (60 per cent) are of Carboni- 

 ferous limestone, most of the remainder consisting of Weulock 

 limestone. It is thus a remarkable fact that these conglomerates 

 are essentially limestone conglomerates, but contain the debris of 

 various rocks down to and including the Woolhope limestone. 



The Trappoid Breccia was so called because it is largely 

 made up of angular blocks of the compact felspathic lavas and tuffs 

 which were formerly known as " traps." They are really rhyolites, 

 hornstones, felspathic tuffs, grits, and agglomerates, and have 

 evidently been derived from pre-Cambrian rocks like those which 

 are known to occur in the Lickey Hills, at Barnt Green near 

 Birmingham, and at Nuneaton. With these are associated many 

 fragments of Llandovery sandstone and a few of Woolhope 

 limestone. 



Mr. King remarks that the difference between the assemblage 

 of rocks found in the conglomerates and that in the breccia may 

 be explained on the supposition that during the accumulation of 

 the former valleys in the adjacent country were being cut down 

 through the Carboniferous and Silurian to the Woolhope limestone, 

 while in the later epoch erosion was continued through the 

 Llandovery Beds, and deep into the underlying Archaean rocks. 

 ' It is also possible that the materials of the two deposits were 

 brought from different directions. 



Another remarkable fact connected with this breccia is that 

 many of the blocks are very large, and that some of them are 

 scratched or striated, the striations resembling those of glaciated 

 atones, so that Sir A. Ramsay was led to infer the existence of 

 glaciers and glacial moraines to account for them. This view, 

 however, has not been sustained, and the striations are now attri- 

 buted to the grinding of rock- fragments against one another during 

 the many subsequent earth-movements which they have experienced. 



This breccia can be traced southward through Worcestershire, 

 where it is often called the Haffield breccia, from its occurrence on 

 Haffield Hill near Great Malvern. This is its most southerly 

 outlier, but others occur on the Abberley Hills, resting on Silurian 

 and Old Red Sandstone. 



The Enville marls are only found in Shropshire, and are 

 not seen farther south than Enville, though they doubtless extend 

 much farther southward beneath the Trias. They include a band 

 of Breccia which near Enville is 50 feet thick, but thins out to 



