ROCKS OF SHROPSHIRE. 653 
At Flax-Hill quarry, 8.W. of Wrockwardine, the purple-banded 
felstones are highly spherulitic. A dyke of earthy rock, a decom- 
posed greenstone, throws off the lavas towards the S.W. The 
felstone is continued for some distance to the S.W., and is seen at 
Leaton, one mile 8.W. of Wrockwardine. 
At about one mile 8.S.W. of Wrockwardine, midway between 
Burcot and the old turnpike on the Shrewsbury road, some very 
interesting rocks are exposed. They are very hard and compact, 
approaching hornstone in texture and fracture, but are clearly frag- 
mental. The contained fragments are green and purple felstone, 
the purple variety being sometimes banded. They vary in size from 
a pin’s head to a pigeon’s egg. Their shape is irregular, their out- 
lines being sometimes well defined, but often shading off into the 
matrix, which is frequently as compact as hornstone. This rock 
has seemed to me to favour the clastic origin of hornstone. The 
beds have a high dip tothe W. Associated with this breccia is a 
compact fine-grained rock, to which also Prof. Bonney assigns a 
fragmental origin (Note 2, p. 666). Underlying these strata, in the 
field to the E., is purple felstone (Note 1, p. 666). 
At Lea Rock, about half a mile W. of the last spot, are the 
banded felstones or altered perlites described by Mr. Allport in the 
Journal of this Society *. Nuclei of quartz, chalcedony, and agate 
give the rock a peculiar spotted aspect. The nuclei sometimes 
open out into geodes lined with quartz crystals. 
The induration which these and other rocks of the Wrekin area 
have undergone is due, I conceive, not to intense heat (for the rock, 
when in contact with intrusive masses, by no means displays greater 
hardness), but to the chemical action of infiltrated waters at perhaps 
very low temperatures. The dissolving power of water is well seen 
in some of the banded felstones, free silica being dissolved out and 
deposited in lines of minute quartz crystals along the lines of lami- 
nation. I haye also noticed in the quartzites that weathered surfaces 
constantly display a coating of recrystallized quartz. The dissolved 
silica may well haye acted as the cement to the flinty hornstones 
and breccias. 
Summary.—aA low rounded elevation, trending 8.W., composed of 
purple and green felstones and hornstones, with some highly indu- 
rated agglomerates, and broken through at intervals by greenstone. 
Bedding not very clear, but a general 8.W. strike, agreeing with the 
strike of the mass, but discordant to the usual strike of the Wrekin 
chain. 
7. Charlton-HMill area. 
Details.—Charlton Hill is an inconspicuous oblong elevation, three 
quarters of a mile from N. to 8. and half a mile from E.to W. The 
northern half is composed of tuff of the Lawrence-Hill type. This 
passes down towards the 8. into a massive bed of conglomerate (Note 3, 
* Vol, xxxiii. p. 454, 
Q.J.G.8. No. 140. 2Y 
