270 A. R. Andrew—The Dolgelley Gold-belt. 
Secondary enrichment is in this district only of slight importance ; 
there is an absence of oxidized minerals in the outcrops, and there is an 
absence of the minerals which are usually considered to be characteristic 
of a zone of secondary enrichment. 
‘The association of minerals found in the lodes, and especially the 
pyrrhotite, suggests deep-seated lode formations, i.e. lodes formed 
at some considerable distance below the then existing land surface, 
but which, owing to denudation, are nearer to the land surface 
existing at the present day. 
With regard to the existence of small traces of gold in the country 
rock of these lodes, I was unable to determine whether such existed or 
not. Maclaren (38, p. 508) had made some assays, and had found 
minute traces (‘0007 grain of gold per ton) in some of the country 
rocks; but it is not clear whether such gold, even if it could 
satisfactorily be proved to exist in the country rock, had not really 
been introduced into the country rock from the veins. 
From this account of the gold veins of the Dolgelley Gold-belt, it 
may be inferred as most probable that as the mines working on lodes 
that outcrop in the black Clogau Beds work down below that horizon 
they will leave behind them the rich pockets of gold. Although it is 
possible that a cross-course conveying gold precipitants may cause the 
formation of a pocket at this lower depth, still it is not very likely. 
Those mines which operate on lodes outcropping in the Vigra and 
higher beds will, if they work down to the Clogau horizon, improve 
their chances of striking rich pockets of gold; it is possible, however, 
that they would not survive to work down to that depth. Where the 
lodes cut across the Clogau Beds it is most probable that the rich 
pockets are dependent for their position on the occurrences of cross- 
courses. 
In examining the lodes underground it is difficult to acquire 
information regarding the associations of the richer pockets. In 
most cases it is no longer possible to examine the places where the 
richer pockets were found. Really, such examination could only 
satisfactorily be carried out by one who constantly visits the working 
faces and notes down all particulars which may have a possible 
bearing on the occurrence of these greatly coveted bonanzas. In an 
American mine this would be done by the mine geologist, whose 
special duty it is to collect geological data regarding the ore-deposits ; 
but as such an official does not exist in English mines we can only 
hope that a substitute may be found in one of the regular mine 
officials, whose duty causes him to inspect the working faces day 
by day, and whose love of research prompts him to record all the 
geological facts that come within his observation. 
Professor Lapworth, of Birmingham University, has aided me 
greatly in the preparation of this paper: he has spent many days 
with me in the field; he has shown me through the sequence of 
beds; he has given me the benefit of his experience in the laboratory 
and office work connected with this paper: for all of these aids 
and also for his never varying encouragement, I am truly grateful. 
To the officials of the St. David’s Gold Mining Company, and 
especially to Mr. Nicholls, the general manager, I am very much 
