STRUCTURE OF SOME SHROPSHIRE ROCKS. 667 
is more distinctly fragmental, and the bands of ferrite and opacite, 
with which occasionally occur slightly larger fragments of felspar and 
quartz, give the rock, as in the hand specimen, the appearance of 
one banded by deposition rather than by flow. It might be formed 
of the finest dust of such volcanoes as produced the Wrekin rhyolites, 
or by the denudation of such rocks. 
(3) Charlton Hill.—This rock consists of well-rounded fragments 
in a matrix which resembles a mixture of decomposed felspar and 
chlorite. Among the fragments I recognize the following varie- 
ties :—(a@) a fragment of very typical granitoidite with character- 
istic quartz, finely banded plagioclase, and a mica (? paragonite); 
also one or two smaller fragments, possibly of the same rock; (b) a 
rock apparently consisting of decomposed felspar and chlorite, in 
general appearance rather like diabase, probably a schist; (¢) a 
rather schistose fragmental rock, consisting of quartz, chlorite, and 
decomposed felspar; (d) a rock having a fine granular ground-mass, 
with some viridite pseudomorphs, some nests of quartz, with viridite 
and (?) epidote, origin doubtful, but probably clastic; (¢) a quartzite; 
(f) a quartzose rock, consisting of long angular quartz fragments in a 
rather fibrous fine-grained matrix, containing probably a little of a 
chloritic mineral. 
(4) Caradoc.—This rock is undoubtedly clastic, though at first 
sight it resembles, to the eye, a fine-grained granite. The fragments 
are more or less rounded and about equal in size; they compose the 
greater part of the rock, the interstices being occupied with a finely 
granular rather earthy-looking matrix. Quartz predominates 
among the fragments; it contains the dusky-looking enclosures, which 
show an approach to a linear arrangement rather characteristic of the 
older rocks both here and in Wales; there is a fair amount of felspar, 
much of it orthoclase, showing sometimes a cross-hatched structure 
(? a little microcline), and some plagioclase. Some of the felspar is 
very full of enclosures; we find also fragments of a brown glassy- 
looking rock, some of which show fluidal or spherulitic structure, 
and closely resemble the Wrekin rhyolite. There is a good deal of 
scattered ferrite and opacite, with microliths of chlorite, epidote, 
and apatite (?). The appearance of the slide induces me to believe 
that its material has been derived from the rhyolitic and granitoid 
Wrekin rocks. 
(5) Hope Bowdler.—A base, apparently glassy, but rendered 
almost opaque by ferrite staining, and crowded with acicular felspar 
microliths. Several larger crystals of felspar are scattered about 
the slide, both plagioclase and orthoclase being, as usual, recognizable; 
they are very full of microlithic products, ferrite, minute enclosures 
of dark glass (?), &c., also a few grains of a greenish mineral, pro- 
bably decomposed augite or hornblende. One crystal shows the 
characteristic cross section of the former; needles of apatite are 
sometimes associated with these. ‘There are, as usual, larger grains 
of iron peroxide. The slide exhibits numerous darker patches with 
well-defined rounded outline; these seem to correspond in all respects 
with the rest of the slide, except that they are coloured by a black, 
instead of a brownish peroxide of iron. 
