44 
THE HALL. 
Messrs. Pickford, Winkfield, and Co. This specimen exhibits 
the apatite in association with a variety of mica known as 
phlogopite. The Canadian apatite is most abundant in the 
townships of Burgess and Elmsley ; the present specimen was 
obtained from North Burgess Mine, Perth. The mineral has 
economic value, since, by treatment with sulphuric acid, it is 
converted into a soluble superphosphate, which is highly prized 
by the agriculturist as a fertilizing agent (p. 1 1 0). 
By the side of the Canadian phosphate is a fine sample of 
phosphorite, or impure phosphate of lime, from StafFel near 
Limburg, on the Lahn. 
Portion of a Vein of Gold-bearing Quartz. No. 162. 
The discovery of gold in California, in June 1848, produced 
an extraordinary amount of excitement in this country and in 
the United States. The gold from the deposits in the beds of 
the tributaries running into the Sacramento, and in the alluvial 
valleys of the country, becoming, from the eager search which 
was made for it, unequal* to the desires of the adventurers, the 
quartz-lodes, which were discovered in the rocks, became the 
objects of exploration. Numerous mines were opened, and 
workings commenced upon these quartz -veins on an extended 
scale. The specimen exhibited is from the Grass valley, Nevada 
county, and was presented by the late Mr. F. Catherwood ; it 
fairly represents all the average conditions of the gold-bearing 
quartz-lodes, not only of California, but of Australia and other 
countries. Small particles of gold are here and there visible, 
and gold is disseminated through the mass, but so finely divided 
as to be invisible. Some very rich fragments of gold * quartz are 
in the same Case. 
An exceptionally fine specimen of crystallised Quartz 
(No. 134), from Weardale, in Durham, is mounted on a Pedestal 
in the north-west corner of the Hall, close to the entrance to the 
passage, covered by a red curtain, leading to the Offices. In the 
opposite, or north-east, corner is a very fine block of Cannel (No. 
53), from near Wigan, in Lancashire, and a few fossil tree-trunks 
from the Coal Measures. (Nos. 52, 54, 55.) With these are 
placed some examples of silicified wood, from the ‘Dirt- bed ’ of 
the Purbeck series in the Isle of Portland (No. 56), and from the 
so-called fossil forest near Cairo in Egypt. (No. 100). 
