246 PROCEEDINGS OF SECTION C. 
group we recognise tin veins, which we have reason to believe 
have been deposited by solutions emanating from the 
eruptive rocks. The conclusion is here irresistible that the 
other varieties have been deposited either from the same 
solutions which formed the tin veins or from other solutions 
which had the same source. 
Gold Quartz Veins. 
The plutonic theory has been proved to be particularly 
applicable to gold quartz veins in some very conspicuous 
instances. The most complete demonstration is furnished by 
J. E. Spurr*, who has shown that the gold quartz veins 
in the district of Yukon, in Alaska, contain a large number 
of accessory minerals which are characteristic of the peg- 
matite veins. Further, he demonstrated that the quartz- 
veins pass over by gradual transitions into aplites, or finely- 
crystalline quartz feldspar dykes, and also into pegmatite 
veins. G. F. Becker+ also has recorded that the gold 
veins of the southern Appalachians contain 62 accessory 
minerals which are characteristic of pegmatites, among these 
being tourmaline, cassiterite, apatite, orthoclase, albite, gar- 
net and scheelite. 
Several localities in Tasmania furnish evidence of the plu- 
tonic origin of gold quartz veins, though I have not heard of 
any evidence from the recognised goldfields ; with these I am 
not personally acquainted. The most striking instance is 
that of the Echo Mine* near St. Helens. We have here 
what I believe to be an intermediate type between gold 
quartz veins and aplite dykes. The formation is about 40 
feet wide, with an extremely silicious aplite rock on either 
wall, and quartz with some pyrites, markasite, and pyrrho- 
tite in the centre. The aplite consists of much quartz with 
relatively small quantities of feldspar and muscovite. The 
aplite is less acid at its contact with the wall-rock than at 
its contact with the quartz, and there is no sharp line of 
division between the two. Tourmaline crystals are occasion- 
ally seen in the quartz and embedded in the pyrites. 
From these examples and from many others that might be 
given we may draw the following conclusions : — 
1. That, besides the deposits like tin veins, apatite veins, 
and contact metamorphic deposits, which represent the first 
deposition of ores from plutonic waters, there must be many 
* Geology of the Yukon Gold District, Alaska. 18th Ann, Report of 
the U.S. Geol. Survey. 
+ Goldfields of the Southern Appalachians. 
t G. A. Waller. Report on the Mining Districts of Scamander 
River and St. Helens. 
