26 
PERMIAN BRECCIA OF LEICESTERSHIRE. 
Feb., 1892. 
I.—Syenite. 
(10, 38.*) There are two fragments of rock which bear 
macroscopically considerable resemblance to the “ southern 
syenites” ofCliarnwood, appearing fairly coarse compounds of 
reddish, whitish, and dark green minerals. Both have 
externally a corroded aspect, one, a rather pyramidal 
fragment, about 2Jin. long by ljin. each way at the 
broader end, seems quite unrounded, and the other fragment 
is probably from an angular mass. Microscopic examination 
shows some quartz ; felspar, hornblende with alteration pro¬ 
ducts, and more or less decomposed ilmenite, set in a micro¬ 
graphic matrix of quartz and felspar. Allowing for the greater 
decomposition, these rocks correspond with the syenites of 
Markfield, &c., to the description of which I refer for details.! 
II. —Felstone, &c. 
The next group of rocks consists for the most part of 
fragments of felstone, varying from very compact to minutely 
granular. In form they exhibit gradations from angular to 
subangular. (35.) The first shows scarcely any rounding, 
and bears macroscopically and microscopically considerable 
resemblance to the purple porphyritic dacites which occur as 
fragments in the volcanic agglomerates of Charnwood, and it 
is not very unlike the uncrushed Sharpley rock. Parts of the 
slide, however, exhibit a subspherulitic character, and there 
are traces of fluidal structure ; perhaps, also, of slight 
mechanical disturbance. (53.) The second is an angular 
fragment of a pale reddish rock, slightly spotted with green. 
Under the microscope, quartz and felspar crystals, of rather 
fragmental aspect, are seen to be somewhat thickly set in a 
devitrified matrix. The structure may be partly due to flow, 
but strain shadows in the quartz and other appearances 
suggest a possibility of mechanical disturbance. This speci¬ 
men also presents some resemblance to certain rocks in the 
northern part of Charnwood. (62.) The next specimen 
apparently is broken from a more rounded mass, and is of a 
purplish tint, with lighter and darker specks. Under the 
microscope it proves to be an altered dacite, and bears much 
resemblance, in the condition both of the quartz and felspar 
and of the ground mass, to specimens which I have described 
from High Sharpley. The rock has been affected by sub- 
* The numbers are those on Mr. Gresley’s specimens, 
f “Quart. Journ. Geol. Soc.,” Vol. XLVII. (1891), p. 101. T. G. 
Bonney, “ Note on a Contact-structure in the Syenite of Bradgate 
Park;” and “Quart. Journ. Geol. Soc.,” Yol. XXXIV. (1878), p. 215, 
E. Hill and T. G. Bonney, “ The Pre-Carboniferous Rocks of Charn¬ 
wood Forest.” 
