32 
PERMIAN BRECCIA OF LEICESTERSHIRE. 
Feb., 1892. 
are often cracked, resemble the quartz from a rhyolitic rock, 
and appear, in one or two instances to contain enclosures of 
devitrified ground mass. Some of them show the polygonal 
markings noted in No. 1 ; ( b ) rather more rounded fragments 
of rhyolitic rock and scoria, exhibiting many minor varieties 
of structure. They are devitrified and generally ferrite- 
stained. Many of them may have come from Charnwood, 
but some exhibit structures which I have not noticed in the 
rocks of that region. There is also a fair-sized grain of 
quartzite. Its quartz grains are pretty clean, and the 
secondary quartz is sometimes in optical continuity with an 
original grain. (24.) This is composed chiefly of subangular 
to rounded grains of quartz, of a compact Indian-red, volcanic 
rock, and of a pale greenish-grey minute grit or mudstone. 
The green grit fragments are more angular, while the red 
felstone are more rounded. Some of the quartz grains with 
more or less polygonal cracks, and with enclosures of the 
ground mass (?), remind me of those in the Peldar Tor rocks. 
I doubt if the volcanic materials came from Charnwood; 
they present a different aspect and show no signs of crushing. 
As a whole they seem a little more basic in character. There is 
much palagonite in the slide, especially in the above-named 
grit. (1.) A piece with larger fragments contains indubitable 
scoriae, well-rounded, almost certainly water-worn, with other 
rounded fragments of volcanic rock in various stages ; some 
are deep iron-red, some much stained with a green cliloritic 
mineral, some almost black ; they probably exhibit varieties of 
rock with a silica percentage from about 50 to rather over 60. 
One fragment resembles a rather impure quartzite, and 
another, which is subangular, consists of quartz with cracks 
forming a kind of honeycomb pattern. These prove to be mostly 
lines of minute cavities, but some appear to be true cracks. (42.) 
Apparently a similar rock, with rather small fragments and 
less of the green-grey constituent. A coarse grit rather than 
a breccia. (2.) A subangular piece of breccia. The fragments, 
which are imbedded in a gritty matrix, consist of grey-green, 
fine-grained grit, with occasionally a few larger grains,probably 
of a red felstone, both resembling those already described 
(cf. 24, &c.). (118, 119, 117.) Two similar specimens from 
Overseal, somewhat rounder, and a third from Stanton, only 
differing in being rather finer grained. (18.) A fine-grained 
variety of the uncleaved volcanic grits of the Permian breccia. 
The constituents include fairly well rolled pieces of various 
volcanic rocks, often showing a fluidal or scoriaceous character, 
probably derived by denudation from cones, the materials of 
which were of an andesitic type. Also some rather angular 
quartz grains occur with the polygonal markings already 
