Genesis of the Gold-Deposits of Barkerville. 415 
April 27th.—J. E. Marr, Sc.D., F.R.S., President, 
in the Chair, 
The following communications were read :— 
1. ‘On a New Species of Hoscorpius from the Upper Carboniferous 
Rocks of Lancashire.’ By Walter Baldwin, Esq., F.G.S., and William 
Henry Satcliffe, Esq. 
2. ‘The Genesis of the Gold-Deposits of Barkerville (British 
Columbia) and the Vicinity.’ By Austin J. R. Atkin, Esq. 
The gold-bearing area of Cariboo (British Columbia) is roughly 
confined, within a radius of 20 miles of Barkerville, to the band of 
varied crystalline rocks known as the Cariboo Schists, generally 
assigned to the Lower Paleozoic Group. ‘The veins follow the strike 
but not the dip of the rocks, the gangue is similar to that associated 
with the nuggets in the placers, and the reefs show very little or no 
oxidized ore. While all the reefs carry gold in greater or less 
quantities, none have been found rich enough to account for the 
placer-gold. It is the opinion of the author that the placer-gold 
has probably been derived from the enriched outcrops of the veins 
which once existed above water-level. Such enrichment is due to 
two causes: firstly, the leaching-out of pyrites leaving the less 
soluble gold in lighter, honeycombed quartz; and, secondly, to actual 
enrichment by precipitation. This may be due to the solubility of 
gold in solutions of ferric sulphate, derived from the decomposition 
of the pyrites. While the enriched zone was being formed, the 
weathering of the surface kept removing the leached outcrop, and 
constantly exposing fresh surfaces to atmospheric influences. To 
the weathering of these outcrops the rich placers are attributed. 
Some of the nuggets in the latter show no signs of attrition, as 
though they had been carried to their present position enclosed in 
a soluble matrix which was afterwards removed. The denudation 
of the reefs and the deposition of gold in the gravels appear to have 
taken place in Tertiary times. 
May 11th.—Horace B. Woodward. Esq., F.R.S., 
Vice-President, in the Chair. 
The following communications were read :— 
1. ‘On some Quartzite-Dykes in Mountain-Limestone near 
Snelston (Derbyshire).’ By Henry Howe Arnold-Bemrose, Esq., 
Maa G:S. 
At Snelston, 33 miles south-west by south of Ashbourne, there 
is an inlier of Mountain-Limestone surrounded by Keuper Marl. 
It is roughly elliptical in shape, the major axis extending for a 
distance of about half a mile north-north-east and south-south-west. 
The limestone is generally massive, with a few chert-nodules in 
the upper parts ; the rock in many places has a broken appearance, 
and it contains small hollow spaces ; the large portions of the lime- 
stone have been partly or completely dolomitized. The floor and 
faces of the quarry are traversed by vertical veins or dykes of 
cealeite, fluorspar, barytes, calcareous sandstone, and quartzite. 
The quartzite of these ‘ dykes’ is described microscopically. It 
consists of augular detritus, quartz-grains with enclosures, a few 
small grains of telspar, and a few shreds of mica. The grains are 
