234 JOURNAL OF THE PLYMOUTH INSTITUTION. 
constituent being absent. It is therefore not typical granite, but 
semi-granite or ‘aplite.” 
The most beautiful red granite of Devon is supplied by Trowles- 
worthy, and there is no richer red to be found anywhere than its 
darker varieties. Those examples which contain schorl are the 
most effective; but the gradations are manifold between the 
deepest red and the palest pink. The texture is fairly even, 
felspar predominating, and mica by no means prominent. Indeed 
a good deal of the rock may be termed—in its absence—a 
* schorlaceous-pegmatite.” There are veins of a compact, fine- 
grained red variety ; and some in which the schorlaceous portions 
are segregated from the more felspathic, which would be very 
ornamental in mass. 
Veins of red granite occur also near Shaugh, at Hanger Down, 
and in the upper valley of the Tavy, among other localities, 
Further local varieties of granite that claim special notice are: 
a pink schorlaceous rock at Leather Tor; a very fine-grained pink 
vein, with a little black mica and schorl, at Brazen Tor; a similar 
vein at Eylesburrow; a fine-grained pink porphyritic vein at 
Ringmoor, nearly approaching to an elvan; a fine-grained dark- 
grey granite with black mica at Sheepstor. 
Though out of our immediate district, a singular form of granite 
from South Caradon Mine cannot be passed over. It is so far 
normal that it contains the usual constituents—felspar, quartz, 
and a little mica. There are, however, two felspars—one well 
crystallized and compact, bright red in colour; the other less 
abundant, white, intimately associated with the quartz, and 
thoroughly kaolinized. There is likewise a chloritic-granite, and a 
cupriferous form strongly tinged with green carbonate. Granite 
with fluor has also occurred in the neighbourhood. 

Elvan.—This is a local Cornish name for a variety of felstone— 
a rock chiefly composed of felsitic matter, and in which either 
quartz or felspar is commonly developed porphyritically, and 
mica not unfrequently occurs. Its ultimate composition is in the 
main much the same as that of granite, and rocks of all stages of 
intermediation may be found between the two. Most of our 
 elvans, from the development of quartz, are also classed as quartz- 
porphyry. Felsitic matter has been defined by Mr. Rutley as 
an “intimate granular-crystalline, micro-crystalline, or crypto- 
