128 Dr Lauder Lindsay on the Place and Power of 
the geological scale. It hardly occurs to any extent in 
Britain; but it is abundant in some parts of Germany, and in 
Iceland it constitutes the ‘‘ Surturbrand,”’ of which I have seen 
specimens very like those of the Otago lignites. To this class of 
rocks—to the tertiary lignites—belong, in my opinion, all the so- 
called Otago coals I have as yet seen. I have traced the formation 
of your lignite from the state simply of decayed wood to that of 
a black coal-like mineral, in the cliffs near the Coal Point at the 
mouth of the Clutha; and I have seen it in process of formation 
at the present day in a well sinking at a depth of some 40 or 50 
feet in the swamp-clays of Dunedin. The origin of these lignites 
seems comparatively recent: they have not been subjected to the 
same enormous pressure as the Carboniferous system coals, occur- 
ring as the former do mostly on or near the surface. Nor do 
they seem composed of the same materials—at least in the same 
proportions: chemically, their constitution is not precisely the 
same; in heat-giving, gas-giving, and steam-giving power, they 
are likely to prove inferior to the true coals, with which they will 
not probably be able to compete.* Should all the coals of Otago 
belong to the family of the tertiary lignites, I fear you must be 
prepared to find their value inferior to that of the true coals of 
Scotland or England, or of coals belonging to the Carboniferous 
system, or to the other systems older than the Tertiary. I have 
been asked whether there is no chance of the discovery of true coal 
in connection with any of the numerous Otago limestones. This 
point I am not in a position to determine; it is an interesting 
problem for solution by your Provincial geologist. Should what is 
called by geologists the ‘“*‘ Mountain Limestone” be found in Otago, 
true coal may reasonably be lookedfor. But the limestones I have 
met with, so far as I can at present venture an opinion, seem of a 
more recent age, and are not of a kind usually associated with coal. 
Lignites you possess in abundance: for they are scattered in beds 
of greater or less extent very generally over the province. They occur 
in, and they are probably co-extensive with, the older tertiary auri- 
ferous “ Drifts,” which constitute one of the most marked features 
of Otago geology. One of the largest workings in the Dunedin 
district, perhaps in Otago, may be seen at Saddlehill, on Mr — 
Jeflrey’s property of Saddlehill Park, on the flank of the hill 
looking towards the Taieri Plain. Lignites crop out at various 
points on the slopes or base of this hill, or in its immediate 
* This impression is so far borne out by the analyses, since my return 
home, by Dr Murray Thomson of Edinburgh, of a series of the Otago lignites. 
His analyses embraced 8 series of samples, including Saddlehill, Clutha, 
Abbott’s Creek, and M‘Coll’s Creek, lignites. Among the results is the follow- 
ing—that they are comparatively poor both in oz/ and gas :—the highest pro- 
portion of o7/ per ton being 17 gallons (Saddlehill), and of gas 3931 cubic feet 
(M‘Coll’s Creek). I reserve details for future and separate publication. 
~_ sr 
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