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new information on a subject of so much importance to the Province.

Unfortunately, the drain, which shortly before my arrival had been in good order, had in some way or other become choked up, so as to make it impossible for me to visit the principal drive.

This was much to be regretted, as many valuable data would doubtless have come within my observation. However, being accompanied by one of the miners, who gave me the necessary information on the spot, I was, nevertheless, enabled to gain a general insight into the results obtained.

The Kowai Coal Mining Company have driven two galleries, and not only connected them with the Government drives, but have also driven cross galleries from the latter.

In my former report, I stated that part of the older carboniferous rocks in the basin had been destroyed, and that they had been replaced by young tertiary beds, so that in some instances they nearly followed the same strike and dip.

The most conspicuous instance of this occurrence is to be seen a few hundred feet south of the drive mined by me on behalf of the Provincial Government. The Kowai Coal Mining Company has here driven a gallery of a few chains, following a seam of a few inches in thickness, and of a very inferior lignite.

Not being able to enter this drive, I had to content myself with examining the specimens of rock which were excavated from it; but I could see no other rocks than those indicated by the face of the cliff where the drive enters, and, in reference, which I mentioned in my former report, that the old carboniferous rocks had been replaced by deposits of a much more recent age, and which would never yield any workable coal seams.

For the reasons already stated, I could not enter the main drive, excavated into the carboniferous rocks, but the few data which I obtained on the spot, fully confirmed my former statements, based upon sufficiently clear and conclusive results, and obtained nearly two years ago, in the two galleries driven on behalf of the Provincial Government, viz: that we meet here with the edge of a large coal basin, the seams thinning out or sometimes disappearing altogether; that the direction of the strata is sometimes changed, for which we may easily account, by bearing in mind that it is at the edge of a basin where the strata are more liable to be disturbed than in the centre, and lastly, that only by boring, could a satisfactory result be obtained.

Of the borings undertaken, that on the right bank of the Kowai, below the terrace, was useless, as it was on the boundary of the carboniferous and the underlying older palaeozoic rocks, and the other in the riverbed of the Kowai was too close to the mouth of the main drive, and was not carried down to the proper depth.

But a most interesting and suggestive fact was revealed by a cross-drive, excavated by the Kowai Coal Mining Company, in a north direction from the gallery excavated under my superintendence, to the description of which I shall devote a few words.

In my former report, I stated that during the formation of the carboniferous rocks in the Kowai, eruptions of augitic greenstone had taken place, as shown not only by greenstone ashes or tufas deposited upon the first few small layers of vegetable matter, but also by the fact, full of suggestive instruction, that these small seams of coal were changed into cinder-like beds, with prismatic partings.

From these observations, made in the drive, I concluded that these eruptions had taken place in the neighbourhood.

Now, after having excavated the cross-drive in question for about a chain, the miners came upon dyke-like masses of a very hard greenstone, from which the beds of greenstone tufa which I passed through had been derived, and which, on examination, proved to be augitic greenstone or diabase; and thus my former conclusions were fully verified:

But I must confess, that I did not expect this greenstone so near to the drive in question, and that I attributed the metamorphic action, as observed in the lowest seams of the Kowai coal measures, rather to secondary causes, than, as now ascertained, to primary ones, the more so, as nowhere in the neighbourhood had I observed any eruptive rocks in situ.

The close neighbourhood of these diabases to the coal measures, does not in any way change my previous conviction, that by boring more towards the centre of the basin, we may meet with larger seams of coal, regularly striking and dipping at a much smaller and more workable angle, the more so, as the greenstone eruptions took place before the deposition of the principal seams, and even were this not the case, have we not many instances in well known coal fields in the old world, that trap dykes break through them without changing either the character of the coal or so disturbing them as to impede their working.

Of course, I have to repeat, that there may be many disturbances which are hidden from us, throwing the seams into such a position, that either they cannot be reached or are not workable when reached; but as this coal field is of importance not only to Christchurch alone, but also to the whole of New Zealand, the expense of thoroughly efficient borings could not be considered lost, even if the results did not answer our just expectations.

Geological Survey Office,
Christchurch,
Sept. 11th, 1863.

Sir,—In accordance with your instructions, I have examined the lignitiferous tertiary basin lying behind Big Ben, the northern summit of the Thirteen Mile Bush Range; but as no new facts of importance were added to the knowledge I obtained of the character of the district two years ago, it is unnecessary for me, in this report, to do more than present you with the results of my previous examination.

They will tend to show you, that the coal which we find there, is a lignite or brown coal, and not a true coal, and as lignites of nearly the same quality are found nearer Christchurch, which can be obtained with little cost, I considered it not of sufficient value to have induced me to recommend the Provincial Government to lay a reserve upon it; the more so as this small basin is rather difficult of access.

During the last week, I learnt that persons may possess some knowledge of practical mining without even knowing the difference between true coal and lignite, although both minerals may be easily distinguished by their different specific gravity, lustre, fracture, streak, &c. As this want of information may lead to heavy losses among our community at large,