BASAL CAMBRIAN ROCKS OF SHROPSHIRE. 411 



in certain parts towards the west, but becoming almost horizontal 

 through disturbance. The compact halleflintas show no bedding, 

 but lie on all sides of the masses of grit, some of whose beds, if con- 

 tinued, would run into them. No grit is visible on the other side of 

 the road. These masses seem to be portions of later deposits caught 

 up and folded in with the older rocks, both here and on the summit 

 of the hill. They do not, therefore, form part of the volcanic series. 

 Nevertheless, since these foldings took place before the deposition of 

 the quartzite, these grits must be older than the latter. On the next 

 bare boss to the west there is another mass of grit intervening 

 between rhyolite breccias and quartzite on the surface, but the 

 relations of this are not very clear. 



On the southern end of the Wrekin, east of Primrose Hill, there 

 is a considerable mass of conglomerate rock forming an elevation 

 and bearing considerable resemblance to that on Charlton Hill. li- 

 aise appears to lie between the quartzite and the rhyolite (see 

 fig. 8). It has, however, so mongrel a matrix that we seem to be 



Fig. 8. — Section from Charlton Hill to the South end of the WreJciu. 

 ([Scale about 14 inches to a mile.) 



approaching the agglomerates of Lawrence Hill. With these latter, 

 however, we should have to compare, not the red grits of Cardington, 

 but the great breccias there exposed at Woodgate quarry and fully 

 dciscribed by Dr. Callaway, who ascribes them and, I think, justly, 

 to the true volcanic series ; but which, it must be noted, occur only 

 on the edge of the mass, and may therefore be the youngest, in spite 

 of their actual dip. 



I think we may reconcile all these observations by looking on 

 the Lawrence Hill and Woodgate deposits as the earliest results 

 of denudation of the volcanic products, and almost belonging to 

 tlieir epoch. Then come the Charlton-Hill and South-Wrekin 

 conglomerates, and possibly that on Willst one Hill, which is very 

 like them ; and lastly, at a later stage, the conglomerate of Wartle 

 Kuowl, followed by the red grit of all the localities that have been 

 mentioned. We must conclude also tliat all this took place before 

 the deposition of quartzite. The explanation involves, however, 

 three conclusions, which rest, of course, on independent evidence, 

 which will be strengthened, if this be accepted as reasonable. These 

 are : — 1. That the Cambrian grit lies unconfonnably, not only on 

 the slates and grits of the Longmynd, but on the volcanic rocks on the 

 east of the fault. 2. That these volcanic rocks are younger than the 

 Longmj-nd rocks. 3. That all of these are anterior to the quartzite. 



I pass next to the porphyry of Hope Bowdler and Cardington 



