Huttron.—On the Thames Gold Fields. 277 
formation ; while (at page 91) he says that at Driving Creek “no proper 
volcanic rocks have ever been met with in the underground workings when 
they have proved auriferous.” Again, this “grey tufaceous sandstone” of 
Tokatea is called by Dr. Hector in another place (p. 96) “greenstone tuff,” 
while Mr. Davis (p. 97) calls the same rock *trachytie tufa" Again, at 
Tapu, what Dr. Hector calls (p. 98) “ greenstone porphyry,” Mr. Davis calls 
(p. 99) * older trachytic breccia.” Dr. Hector, also, although he acknowledges 
(Trans. N.Z. Inst., IL, 367) that the bed rock of the auriferous lodes is the 
same both at Coromandel and the Thames— and therefore, according to him, 
“greenstone tuff” or “green tufaceous sandstone"— calls (Trans. N.Z. Inst., 
I., 48) the bed rock from the Golden Crown Claim a *felstone." It seems, 
therefore, to me that Dr. Hector has entirely failed to distinguish by litho- 
logical characters the difference between his two formations ; and I may remark 
that no greenstone tuff, nor any other basic tufaceous rock, has ever yet been 
brought from the Thames, and that the term “ greenstone tuff” is altogether 
a misnomer. Of course all agglomerates formed by the latest eruptions would 
be considered by Dr. Hector as belonging to his younger formation, and it is 
quite true that they never contain gold ; but I shall presently show how it is 
that these superficial accumulations could not be expected to contain gold in 
any quantity, and that they afford no proof of two formations. 
Great stress has also been laid by Dr. Hector on the supposed similarity of 
the gold-bearing rocks of the Thames with those of Waimungaroa, Batten 
River, Cape Terawiti (Prog. Report, 1866-67, p. 32), Dun Mountain (Trans. 
N.Z. Inst., IL, p. 365; and III., p. 288), and of Gympie, in Queensland 
(Trans. N.Z. Inst., IL, pp. 366 and 399; also Museum Report, 1870, p. 4). 
Putting aside the question whether identity of age can in any way be proved 
by the identity of the rocks from such distant localities,* I must remark that 
having examined rocks from the Dun Mountain, Cape Terawiti, and Gympie, 
I can find but a very superficial resemblance between some of them and some 
of the melaphyres of the Thames, which occur only in dykes, and never contain 
gold veins. The analyses of the rocks from Gympie—which are from the 
identical specimens that Dr. Hector says he cannot distinguish from Thames 
rocks—show that there is a wide difference between them, while the analyses 
of the Dun Mountain rocks (Lab. Report, 1871, p. 17) show a still greater 
divergence from those of the Thames ; the only one that nearly approaches in 
composition to the Thames auriferous rock being No. 9—: а fine-grained 
argillaceous slate, with slaty cleavage.” In fact, the Gympie and Dun 
Mountain volcanic rocks are true greenstone tuffs, while the Thames rock is a 
trachyte of a totally different character to the others. 
* The Gympie rocks have been shown by Messrs. Daintree and Etheridge to be of 
Devonian age, while the occurrence of Jnoceramus in the Dun Mountain shows that 
those rocks cannot be older than the Lias. 
