BASAL CAMBRIAN ROCKS OF SHROPSHIRE. 



409 



part of the western slope. It has a dirty-looking muddy matrix, 

 and contains various fragments, quartzoso, micaceous, and rhyolitic. 

 On Caer Caradoc there are two patches of red grit. One is at 



Fig. 5. — Section across the Volcanic Hills near Church Stretton. 

 (Scale 1| inches to a mile.) 







the southern end, where it is noticed by Dr. Callaway and described 

 microscopically by Prof. Bonney, who says it contains fragments 

 which closely resemble the Wrekin rhyolite, and that its material 

 has probably been derived from this and the granitoid rock, which 

 is exactly the character of the Cambrian conglomerates. The other 

 is on the north side, where only fragments are found, but their 

 position is such as to suggest, though not to prove, that the rock 

 is overlain by the Cambrian quartzite. On the summit of the 

 Lawley there is also an entirely isolated patch of grit, which may 

 belong to the same group, but it is not very like the other exposures. 

 If we pass on to the neighbourhood of Wellington, there are again 

 conglomerates and also grits, but it does not appear that their age 

 is necessarily the same as those already mentioned. There is first 

 the conglomerate of Charlton Hill, which Dr. Callaway regards as 

 of Uriconian age, on account of the stratigraphy of the spot. By 

 the aid of the 6-inch map, and the numerous exposures, I have been 

 able to lay down pretty accurately the actual position occupied by 

 the conglomerate and associated beds on the surface, and to show 

 that it is entirely isolated and surrounded on all sides by igneous 

 rocks. There is also a second patch at the northern-road junction, 

 whose relation to tbe other rocks is not made out. On Charlton Hill 

 itself the conglomerate is quite local (see fig. 7, p. 410). Towards 

 the north-eastern end, where the band crosses the roadway, there 



Fig. 6. — /Section seen in Charlton Lane, showing the Relations of 

 the Grits. (Scale about 1 inch to 00 feet.) 



are some slaty grits, with high dip striking N.W. and pointing 

 directly on one side to diabase, on the other to rhyolite. In the 

 road-section, which Dr. Callaway regards as conclusive (see fig. (5), 

 we find in the northern bank two masses of grit, each with a dip 



