C.—9

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average of the fragments, with larger or smaller, as the case maybe. Breccias continue to the shore of Coromandel Harbour in the line of the Hauraki and Bunker Hill Claims, with, however, dykes or included masses of dark augitic rock. In Kevin's Point, in the sections exposed on the roadside from the wharf to where the road passes on to the alluvial flat of Kapanga Creek, decomposition has reduced breccias and other rocks alike to the condition of a tufaceous sandstone, and their true condition is to be seen only in the material brought to the surface by the various mines of the surrounding district, From the Britannia Mine the eastern boundary of the Kapanga group rapidly declines to lower levels, and south of Kapanga Creek, except in Preece's Point and at the base of the hills east of Preece's Point Peninsula, no prospecting has been carried on in the southern part of this area of tne Kapanga group. Preece's Point Peninsula shows the presence of the characteristic rocks of the Kapanga group, and forms part of the belt of more auriferous country that from Coromandel Wharf trends northeast to the western slopes of Tokatea Hill. This belt is proven by the location of the various claims in which auriferous lodes have been found or are being worked. It may be regarded as being from one to two miles in width. The strike of the lodes is across it, and it might be expected that these would extend into the country to the north and north-west of the line that limits it in these directions. As a matter of fact, whether the reefs do extend or not, failure to discover these or to prove them remuneratively gold-bearing has defined apparently the limits of the auriferous belt along a remarkably straight line on the north-western side of the belt. There seems, so far as the rocks indicate, no reason why the reefs and gold should not continue to the northward, but the fact has to be accepted that the district to the north, and for no lack of prospecting, has not proved productive. The southern limits of the belt are not at the surface so well defined as the northern. This is owing to the rocks being covered up by the alluvial deposits of the Kapanga Flat and the middle course of the stream to the Upper Township. Also, it may be constricted in breadth owing to the presence of the slate on the lower slopes of the Success Range. Between Preece's Point and the northern limit north of Bunker Hill and the Hauraki North Mines its full width appears. This line, belt, or channel of auriferous country—for it is known by these different terms —abuts against that running along the main range on the west slope of Tokatea Hill and the northern part of Success Range, but does not pass through the range to the Kennedy Bay side. Neavesville Area of the Kapanga Bocks. —The rocks of the Kapanga group as develope in this area, with which are included those of the Upper Whenuakite and Boat Harbour, that stretch along the coast-line to near the mouth of the Tairua River, so closely resemble those of the neighbourhood of Coromandel that there need be no difficulty in recognising them. On the west side of the Peninsula they begin in the Kauaeranga Valley, south-east of Table Mountain, and east of the Billygoat Falls they form a narrow outcrop between the great intrusive mass of Table Mountain and the rhyolite rocks that form the higher part of the water-divide between the Upper Kauaeranga and the Tairua Valleys. Underlying the rhyolites they form the deeper-seated rocks of the range, and at low levels are probably continuous through to the Tairua Valley, but on the west side flanked by younger rocks of an andesic character, and to the east, overlain as they are by the rhyolites, they are exposed chiefly by being deeply cut into by the Hihi and other small rivers, tributaries of the Kauaeranga, and on the spurs appear along the middle slope of the range. Opposite the northern sources of the Fourth Branch of the Tairua the boundary sweeps to the southwest and crosses the upper valley of the Kerikeri, two to three miles from the source of that stream. Thence the eastern boundary turns to the south and crosses the upper valleys of both branches of the Puriri, and from the southern sources of the last-named stream the south-east boundary trends north-east to the Tairua River, about two miles above the junction of the Fourth Branch. Rhyolite rocks appear for a short distance up the Fourth Branch of the Tairua, and thence the junction between the Kapanga rocks and acidic rocks in a north direction follows an irregular line, due to the fact that along the Tairua Valley the rhyolites are either intrusive or have been exceedingly disturbed. The contact-line between the two rocks being at places vertical in the low grounds, while at the same time the projection from the north of rhyolite rock in a more horizontal position on the higher part of the main range, and possible outlines of this on the different spurs descending to the Tairua Valley, render difficult the tracing of the boundary on this side, and the difficulty in this respect is greatly enhanced by the exceedingly rugged nature of the country, which towards the north, round the sources of the Hikuwai and Second Branch, is little short of impenetrable and impassable. The area within which mining is carried on at Broken Hills is surrounded on the east, south, and west by rhyolite rock, and is connected with the larger area of these rocks, which, to the east, north, and west is surrounded by rhyolite, the andesic breccias of the Kapanga group reaching to the north a little farther than the east and west line from their first appearance on the west side of the range. Thermal action has been rampant throughout this area, and, besides building up vast piles of siliceous sinter, has charged the rocks with threads, strings, veins, and masses of chalcedonic, flinty, and crystalline quartz, that where these more particularly abound mounds, pinnacles, and peaks remain, while the softer surrounding rock has been removed by denudation. These tower above the general level of the country, yet every stream of any .consequence has cut deep, narrow gorges that twist and wind through and among these harder cores, the centres of thermal action, so that the northern part of this area on the east side of the range constitutes one of the most remarkable sights to be met with in the northern, or, indeed, any part, of New Zealand. In the southern part of the area the outlines, though rugged, are not so intensely so as in the northern part. Here thermal action is displayed on a gigantic scale in the vicinity of Neavesville, and the top of the mountain west of Neavesville is formed of sinter, which, however—what remains of it—is but a fragment of what once was : the whole slope to the north-east into the valley