386 THE DEVONIAN OF CAPE BRETON—GILPIN. 
remainder in glass works, and for the production of fluoric acid 
and other chemicals. In the States fluoric acid to the extent of 
6,000 tons, valued at $3.00 per ton, is produced as a by-product 
from the manufacture of cryolite into various sodium salts, alum, 
aluminium, ete. 
Galena occurs in Jimestone near the head of Arichat harbor, and 
has been prospected several times. The ore carries small amounts 
of gold and, I am informed, up to ten ounces of silver. 
Barytes occur in small quantities near McMillan’s Point, on the 
Strait of Canso. 
So far, the Devonian rocks of Cape Breton have shown the 
greatest mineral value in iron ore, and inferentially it may be 
expected that future valuable discoveries will be made. In strata 
of this age in Annapolis County are known the valuable bedded 
hematites, sometimes altered into magnetites, of Clementsport 
and the Nictaux district. So far, similar deposits have not been 
met in the counterpart of these rocks in Cape Breton. In Guys- 
boro’ County, however, important deposits have been opened, 
and their mode of occurrence has a direct bearing upon the pro- 
bable ore-yielding jocalities on the opposite side of the Strait of 
Canso. At Erinville is a large and important deposit of specular 
ore. Some years ago a test was made of the extent of this 
deposit. A shaft was sunk in the ore fifty feet, and a tunnel 
driven, exposing a body of ore sixty-five feet wide ; another bed 
in the vicinity was twelve feet wide. The ore is fairly compact, 
running from 55 to 62 per cent. of metallic iron, and very low in 
phosphorus, and not holding above the amount of sulphur usu- 
ally found in ore of this character. The walls of the veins are 
composed of greenish, dioritic, felspathic, trappean, brecciated 
rock. About a mile further west, promising indications of ore 
have been found in altered slates, and shales with quartz. In 
the vicinity are large masses of dark gray trap, in contact with 
conglomerate. On the seashore, near the east side of the mouth 
of Milford Haven, are large beds of altered clay slates, veined 
with calespar and quartz, and penetrated by dioritic rocks. 
Veins of ore up to two feet in thickness, of the compact specular 
variety, have been opened here and worked to a small extent. 
