450 
SILURIA. 
[Chap. XIX. 
In North Wales, where similar but older strata have been more crystallized 
and infinitely more penetrated by igneous rocks, gold was not only obtained in 
ancient times, but is still found to some extent. In Merionethshire some of the 
older slaty rocks were twenty years ago announced, by Mr. A. Dean, to be aurife- 
rous*. The district then referred to, which lies to the north of Dolgelly, and to 
the north and west of the small river Mowddach, has since been resurveyed by 
Professor Ramsay, who has described the precise geological relations and mineral 
character of several metalliferous lodes, which, poor in lead and copper, are 
slightly charged with gold f- The lodes are subordinate to the Lingula-flags or 
Lowest Silurian, as well as to the adjacent Cambrian rocks ; and these being tra- 
versed by trap-dykes (including magnetic greenstone), as well as bounded by a 
large mass of eruptive rock, are much altered, often into a talcose and chloritic 
schist, and are traversed by quartz-veins containing much iron-pyrites. The 
principal localities where the gbld had then been observed are Cwm-eisen-isaf and 
Dol-y-frwynog. One of the veinstones at the latter place consists of white sac- 
charoid quartz, in some of which small flakes of gold are distinctly visible to the 
naked eye. Professor Ansted, who has examined the same gold- veins in situ, re- 
ported to me that, at Dol-y-frwynog, the gold is disseminated both in grains and in 
laminaG enclosed in irregular veins, parallel to the Lower Silurian schists, and 
contiguous to a poor lode of copper-ore, the whole lying near a greenstone within 
the slaty rocks. The auriferous bands, he says, are made up of numerous threads 
of quartz and sulphate of barytes, which, besides the grains and flakes of gold, 
contain crystals of galena and copper-pyrites. 
Mr. Warington Smyth, who had previously examined this mine, has devoted 
much attention to other auriferous veins in this district, and particularly to that 
called St. David's Lode, which intersects the Lingula-flags near the old copper- 
mines of Clogau. The lode, which is very definite, although variable in cha- 
racter, has yielded, from workings of moderate extent, probably not less than 
£70,000' worth of gold %. 
At a few places in Cornwall § and Devonshire, gold has long been known to 
exist in small quantities, both in the matrix of mineral lodes and occasionally 
in accumulations of rolled materials. The Poltimore mine, near North Molton, 
Devon (where certain schists of Upper Devonian ? age are mineralized, and were 
formerly worked for copper), was said in 1853 to promise a rich auriferous 
result ; but since the issue of the first edition of this work the speculation has 
been abandoned, it having been proved (as I suggested to the noble proprietor 
would be the case) that no sufficient body of gold-bearing matrix would be found 
to repay the cost of the works. The coarse ancient alluvium or gravel of Corn- 
wall, whence the tin-ore has been extracted, as well as some other portions of 
Drift in that county, have indeed long afforded small quantities of gold ; but, 
although the largest fragments have occasionally been of the size of a pigeon's 
the rock might formerly have been quarried for 
the gold it contained. Suspecting that some 
traces of gold might be detected in the pyritous 
refuse of the quartz-rock, I submitted a little of 
it to the late eminent chemist, Dr. Turner ; but he 
could not detect a trace of the precious metal. 
Subsequently, however, Mr. Warington Smyth 
and Dr. Percy detected a small quantity of gold 
diffused in these quartz veinstones. See Memoirs 
of the Geological Survey, vol. i. p. 480 ; also an 
exposition of the relations of gold, in the ' Lec- 
tures on Gold ' by E. Forbes, Jukes, Play fair, 
Percy, Warington Smyth, and Hunt. 
* Report Brit. Assoc. Adv. of Science, 1844, 
Trans, of Sect. p. .56. 
t Quart. Journ. Geol. Soc. Lond. vol. x. p. 242. 
See also Mr. Eeadwin's notes on the gold-produce 
of this district, read before the British Associa- 
tion in 1863 and 1865. 
I The quantity of gold raised from this lode 
between April 1860 and May 1867, as officially 
accounted for to Her Majesty's Office of Woods 
and Forests, is 12,416 oz. Appearances are at the 
present moment very promising. See Appendix. 
$ Mr. S. R. Pattison read before the Geological 
Society (February 1st, 1854) a notice on auriferous 
quartz-rock near'Davidstow, North Cornwall, the 
chief gold-bearing mass of which is the gossan of 
a dyke in a metamorphosed rock of Upper-Devo- 
nian age, which, mantling round the granite of 
Rough Tor, is also associated with dykes of trap. 
