TRANSACTIONS OF THE SECTIONS. a's 
On the Geology of the Gold-fields of Otago, New Zealand. By W. Lavvrr 
Linpsay, M.D. & F.RS. Edinburgh, F.LS. §& F.R.GS. London, $e. 
The author had made a personal geological survey of the Tuapeka and other gold- 
fields of Otago between October 1861 and January 1862, some of the general results 
whereof were published, under the section on the “ Geology of Otago,” in a Lecture 
by him, printed in Dunedin in January 1862, entitled “ The Place and Power of 
Natural History in Colonization, with special reference to Otago ; being portions of a 
Lecture prepared for, and at the request of, the Young Men’s Christian Association of 
Dunedin,” and issued as a pamphlet by and under the auspices of the said Asso- 
ciation. 
He had also formed and brought home a considerable collection of the rocks and 
minerals of the Otago gold-fields, with relative field-memoranda, maps, and drawings. 
F The general results of his observations and deductions may be tabulated as fol- 
ows :— 
1. The gold and gold-bearing rocks of Otago do not differ essentially, guoad 
mineralogical or geological characters, from those of every other part of the world 
hitherto known to be auriferous. 
2. The original matrix of the gold is quartz; and the latter occurs interbedded 
in, or associated with, metamorphic slates, especially of the gneiss, mica, tale, 
chlorite- and clay-slate families. 
3. These slates vary greatly in mineralogical character; but they bear a closer 
resemblance to those of central and southern Scotland (Grampians, &c.) than to the 
more altered Silurian auriferous slates of Victoria (Australia). 
4, The slates in question are probably of Silurian age; but this has yet to be 
proved, for they are themselves non-fossiliferous ; and as yet the subjacent rocks are 
unknown. 
5. At various points there are evidences of considerable disturbance in the 
schistose strata by the intrusions and eruptions of trappean rocks, apparently refer- 
able to the Tertiary era. 
6. The valleys among the schistose hill-ranges are generally occupied by alluvial 
drifts, apparently of Tertiary age, naturally divisible perhaps into a lower or older 
group, characterized by its abundant lignites, and a superficial or newer series, 
which is chiefly the seat of the operations of the gold-miner. 
7. The lignitiferous or older drift consists chiefly of quartz gravels—in certain 
deposits cemented by means of peroxide of iron and other materials into a hard red 
conglomerate—associated with thinner strata of clays, sands, and gravels. This 
series of beds sometimes occurs at a height of from 500 to 1000 feet above the sea- 
level, on the flanks of trappean and other hills. 
8. The upper or newer drift bottoms—the valleys and “ flats,” so common in 
the hilly parts of the country (where the hills are schistose)—consist essentially of 
(a) clays, blue, yellow, or red; () boulder-clays ; and (c) gravels, so called, which 
are really the little-worn or abraded débris of the subjacent and circumjacent slates, 
and which are more correctly denominated by the miner’s phrase, “ chopped slate.” 
These beds are immediately superjacent (in the order in which they are above 
enumerated) on the generally upturned and very irregular edges of the slates ; and 
the latter, according to their mineralogical character, give a dominant colourt o 
the former,—the clays aud gravels of the gneiss being bluish or greyish, of the 
chlorite-slates greenish, of the mica-slates, in proportion as they are less or more 
ferruginous, yellow or red. 
9. Gold occurs chiefly in the gravel or “chopped slate” above described,—this 
constituting the “ wash-dirt” of the miner. It is frequently found most abundantly 
in “pockets” (hollows or crevices) of the irregular upturned edges of the subja- 
cent slates, whereon the gravel immediately reposes. It is disseminated through 
the clays in some localities; while in others it is sometimes collected in quantity 
in cavicies, or “ pockets,” under the boulders of the boulder-clay beds. 
10. The gold is partly granular or gunpowder-like, partly scaly, nuggety, or 
erystallized ; and it exhibits every gradation, intermixture, and variety of each of 
these forms or kinds in different localities. 
11, It is associated, in different localities, with iserine (titaniferous iron-sand) ; 
