LARGE MINERAL SPECIMENS. 
43 
Large Mass of Native Copper from the Mine at the 
Ghostcroft, Mullion, Cornwall. No. 99. 
Trenance mine, from which this remarkable specimen was 
obtained, was worked near Mullion, close upon the junction of 
the serpentine with the hornblende-schist. It is not unusual to 
find, in the fissures of the serpentine rocks, masses of native 
copper; these have frequently induced a further search for 
mineral treasure, which has rarely been successful. The 
specimen, which was presented by the adventurers, is only a 
portion of the mass as it occurred in nature ; the miners being 
compelled to break it in order to raise it to the surface. 
Part of a Lead Vein or Lode from the Grassington 
Mines. No. 95. 
The Grassington mines, the property of the Duke of Devon- 
shire, by whom this fine specimen was presented, were at ono 
time the most important in Yorkshire. This example shows in 
a very instructive manner the mode in which, ordinarily, lead 
ore occurs in nature. By looking at the transverse section, 
which hangs upon the east wall of the Model Boom (A.), it 
will be seen that the strata in which this lode occurs have been 
dislocated — with formation of a fissure running almost vertically 
through all the beds. In this crack the mineral deposit has, 
taken place ; the mineral here formed being the sulphide of 
lead, or galena (p. 74) associated with sulphate of barium 
(p. 108). ' 
Copper Ore from South Australia. No. 89. 
This large specimen exhibits a superficial coat of malachite > 
or green carbonate of copper, encrusting a fine mass of cuprite, 
or red oxide of copper. These minerals are frequently present 
in the upper part of deposits of copper ore, where atmospheric 
action has penetrated. The specimen before us was obtained 
from the shallow workings of the Great Northern Copper 
Mining Company of South Australia. ( See also p. 89.) 
Apatite from Canada. No. 87. 
Some of the most ancient rocks known to the geologist occur 
in the dominion of Canada, and from their development in the 
Laurentide Hills, north of the Biver St. Lawrence, have received 
the name of the Laurentian series. This system of rocks; 
contains thick beds of crystalline limestone, and in this limestone 
the mineral called apatite occurs. Apatite is a phosphate of lime^ 
associated with more or less chloride of calcium. The Canadian 
mineral frequently presents a sea-green colour and a crystalline 
texture, as seen in the block before us, which was presented by 
D 2 
