GEOLOGY-LECTURE BY DR. HECTOR.

Colonist, Volume XII, Issue 1175, 29 December 1868, Page 3

GEOLOGY-LECTURE BY DR. HECTOR.

Dr. Hector, F.R.S.E., head of the scientific department of the Government, delivered a lecture to a large and fashionable audience, in the Provincial Hall, on Tuesday last, his Honor the Superintendent in the chair. The subject wn 8, "The Geology of New Zealand, more particularly as relating to the Province of Nelson." The lecture was illustrated with large maps and sections of the geological structure of the two islands. Dr. Hector, «fter some introductory mntter with reference to the fundamental principles of geology, and a general description of the fo»mation ar.d depth of the earth's crust, spoke of the existence of deep furrows on the surface of the earth, as lying between the great mountain chains, these furrows being genernlly filled by seas. He spoke, also, of the ' continual action that was going on on the earth's surface, the ceaseless, though slow, abrasions, and •tendy disintegrntion of coasts and mountain lines, their reduction to sediment by the action of water, the upheavals of certain portions and subsidence of others. There was one constant round of change. Touching on the effects of volcanic action, he alluded to the great sea wave which was experienced here on 15th August, and remarked that history did not record any previous instance of an earthquake wave having travelled to far over the surface of the globe. The now commonly received theory regarding sub-marine volcanic action was that a sudden eruption of stenni occurred from large masses of water entering a fissure in the earth's surface and meeting with internal fires which, probably, combined with other forces, had produced the disruption in the crust of the earth. Volcanic hille were formed of material very different in its nature from those great leading ridges of the earth's surface. The remains of past animal life, the fossils found in the various rocks, went to prove that the same type of life existed as in former years; there seemed a continuity of type, leading to the conclusion that there had been no great cnttiplasm in nature so as to break that continuity. The lecturer touched on the formation of certain mountnln ranges on the coasts of New Zealand, and their height, some of them rising 1500 to 2000 or 4000 feet above the ■ea level, and going down, what might be termed, considering the size, almost perpendicularly to a depth of 5000 to 6000 feet. In many cases the line of soundings was very close to the shores of New Zealand, On the West Coast, not far from the shore, he had tried with 700 fathoms (4200 feet), and had found nr> bottom. In referring to the great ocean currents which exist in various parts of the world, and by the. notion of which great changes ware produced on tho earth's surface, Dp, Hector, point-ing to West Capo in the Province of Otago, in the Middle Island, and to the West Cape inTaraliaki on the North Island, said that to these promontories, and the peculiar hardness of the rocks of which fchey were composed, was due the preservation of a large pavt of the islands from total disintegration by the action of the sea. There were no fossil remains of any birds of a distinct rape in New Zealand, and he thought, that the moa mugtj like man, hnve been a pecent settler in this Colony. The strata in New Zealand were of a later kind than those of Britain and Europe. Some remarks were made respecting the action of the water in fomiing estuaries, and he alluded to the estuary of Blind Bay and the continuance of the valley, of which it formed a portion, running through the Moutere and extending to theWesl Coast; and then the lecturer alluded to the differenl kinds of rocks which made a country valuable in s '•bmmercial light. With reference to the gold-boar ing nature of the country, l)r. Hector said th,at the condition of the Thames Gqldfjeld was exactly the •ame as here, with the exception that we had; not any decomposed grapitip rook. 4-* ?ef*Bf> it nY fl 01 yiei been discovered, though there were probabh ippcarftncipi at W«»^Wo»» out they seeme^ b<

destitute of sulphide of tapper and Other -sUlphidtifl which are generally the accompaniments. In' the Western district of the Province, towards the Wnngapeka, good gold had been obtained, and he was rather inclined to believe that the same thing would yet bo found in the North Island, and had great hopes that throughout the South Island we should be able to discover varicus isolated localities, such as had been found at the Thames'. After all, he concluded, one or two men could do but little in obtaining facts of the kind necessary to draw conclusions respecting the geological conditions of certain districts. What was wanted was co-operation.. Those who had .some interest in these matters, and all who had time should take an interest, should gather specimens and preserve them for examination, and by this means collect information which would prove of great value. He also alluded to the establishment of the J\;ew Zealand Institute, and the formation of several societies which had been affiliated thereto. A vote of thanks to Dr. Hector was mover! in complimentary terms, by his Lordship the Bishop of Kelson, and this terminated the proceedings. We have been furnished with the following document, as bearing on one of the subjects alluded to in Dr. Hector's lecture :— Sic,—-I beg leave to hand to you the following report of an examination of D'Urville's Island, made by me of its probable auriferous character. Commencing at the south end of the Island, I found a broad belt of "liac " containing indications of copper, and on the copper mountain, about two miles inland, and northerly, more decided evidences of that metal, culminating in a large and welldefined lode of chrome, accompanied with copper carbonates diffused throughout the ore, but whether in payable quantities or not I am unable to state without testing. This belt of mineral country passes in a northeasterly course, and is to be met wiih largely exhibited at Port Hardy and towards the east and north-east coast of the Island. Although other minerals, including antimony, lead, &c, may be found in this course. I fear no auriferous lodes will be discovered, ail such quartz lodes as I met with being largely impregnated with mica and cobalt, very much so in New Harbor, where a granite course seems to cross through the lias formation. At this point there were some indications of gold, but in trying the alluvial deposits none could be found. The West Coast is entirely composed of porphoitic and non-auriferous rocks, and the middle land, between east and west, consists of mieaeious slate and sandstone of secondary formation, none of the primitive rocks appearing except at one or two points were oceanic disturbances have exposed the schist rock and quartz. A very brief and cursory examination of the wnter courses at these points, leads me to conclude that they do not continue through the Island. , Generally, it has an auriferous appearance, but the utter absence of the usual wash of the goldminer, and of quartz and auriferous rocks in the newer water course, leads me to believe that neither eruption nor disintegration hits sufficiently exposed the mineral deposits of the Island to make them profitably available. In my opinion the deposits of gold will be found south-west of the Island and upon the main land. I am, &c, A. D. M'Tatish. | Nelson, Nov. 14,1868.