C.—9

44

On the opposite side of the range, and a little to the south-west of the Tokatea Saddle, the slates are next met with in the low-level tunnel of the Peveril Mine. They are here cut into after passing 300 ft. of volcanic rock, and their exposure in section extends only 150 ft. along the drive. They cannot, therefore, rise to a great height above this level which is 1,020 ft. above the sea. The rocks thus exposed or cut through are dark-coloured mudstones, sometimes with an indistinct slaty structure. These being overlain by the volcanic rocks, no slates show at the surface till reaching down to the low grounds of Driving Creek. Nor in Driving Creek itself are any slate rocks seen ; although it was reported to me that such are found on the Kapanga Hill, and along the bed of the creek downwards in the direction of the upper township. I made careful investigation, but failed to find the least indication of slate, or of rocks belonging to the Maitai series. The slates, however, show a little to the east of the road, between the western foot of Murphy's Hill and the upper township. They are exposed in the bed of a small creek draining from the Success Range, and form slaty strata of a dark colour dipping to the eastward. This is the commencement of an area of Maitai rock exposed at the surface along the whole length of the Success and Tiki Ranges to nearly abreast of Castle Rock, at the source of the Matawai branch of the Waiau. At first the breadth over which the slate rock is seen is not more than 40 or 50 yds., but, as the rocks are followed to the south, the width of their exposure gradually increases till, on the new road leading to the Success Mine, the exposure is at least a quarter of a mile across and attains a height of 600 ft. above the sea. Where they form the channel and show in the immediate banks of the creeks they are of a darkgrey colour, often veined with calcite, but on the sides of the spurs and in many of the road-cuttings they are, through decomposition, of a pale yellow or buff colour. The dip is generally to the eastward, and at angles as a rule 45° and over. On the Success Road, the last and highest rock seen is a reddish shale, but whether the colour is native to the rock or induced by decomposition of contained pyrites may be uncertain. Volcanic rocks stretch some distance up the spur at the back of Bridson's Store, along the road to the Success Mine which leaves the main road to Kapanga and the Tokatea at Bridson's Store; but following the range south these again descend to the level of the Kapanga Flat, and the slates show in the bed of the creek where the Coromandel-Kuaotunu Road leaves the flat and begins to ascend the range, forming the main water-divide between the east and west coasts of the Peninsula. At first the rocks are alternating beds of sandstone and shale, dipping at a considerable angle to the east, and these, light-grey or buff-coloured, continue for a considerable distance along the road ; but on the track gaining the crest of the ridge by which the main range is approached, a craggy mass of coarse, indura.ted sandstone is met with, round the northern side of which the road, to avoid a heavy grade, has been carried. Beyond, or south-east of this, is a saddle on the ridge, and here again the rocks are softer, finer in grain, and slaty in character. The slate rocks terminate somewhat obscurely by being overlain by volcanic rocks at a height of 650 ft. above the sea, fully half a mile before reaching the saddle by which the road crosses the range. Within the watershed of Pukemaukuku Creek the slates rise to about an equal height, and are of the same character as on the Coromandel-Kuaotunu Road. Sandstones are perhaps more abundant; the heavy bed of coarse sandstone forming the bluff on the road-line being here of greater thickness or lying at a flatter angle. Dyke rocks also disturb the slates and sandstones in the lower part of the spur by which the ascent is made to Aicken's freehold and the neighbouring claims. More to the south the lower western slopes of the outer flanking range shows the presence of volcanic rocks belonging to the Kapanga group, but these again descend to the low ground at the foot of the Tiki Spur. The Tiki Creek, in its lower part, but above where it enters the hills, is cut deeply into alternations of slate and sandstone till reaching forward to the heavy bed of gritty sandstone, the presence of which farther north has already been noticed. Beyond this, towards the upper part and source of the creek, there are several massive dykes of grey crystalline rock, and heavy bands, perhaps intrusive, of more brecciated and much decomposed rock. On the road leading up to the Tiki Diggings the rocks are again, through weathering at the surface, of a light-grey or buff-colour, but near the saddle they change to reddish and purple shales. These latter lie beyond or east of the hard sandstone bar. Further on, beyond the saddle near the Tiki Diggings, these purple rocks continue to be exposed in the cuttings of the track till they disappear beneath the rocks of the Thames-Tokatea group, forming the higher part of the main range. The height to which the slates attain on the Tiki Spur is about 800 ft., beyond which to the south they gradually are found at lower levels, till, in the first creek beyond the Matawai that comes from the Castle Rock Range, they disappear under volcanic rocks. Within the area occupied by the rocks of the Maitai series which begins on the south side of Coromandel Harbour, and thence, uninterruptedly extends along the western side of the Peninsula to Tapu Creek, the rocks are various, but not generally different to those which as belonging to this formation have already been described. Thin contorted strata consisting of harder and softer bands appear at the water's edge on Lynch's farm ; but beyond the bridge where the road to the Thames commences to ascend the hilly country between Coromandel and Manaia Harbours, the rocks are those common to the middle part of the series as seen in other parts of the district —viz., moderately fine-grained sandstones and distinctly bedded argillaceous shales, standing at moderate or high angles, and dipping variously but usually to the eastward. In the middle part of the Manaia Valley this also is the character and disposition of the rocks, although sandstones may be more abundant. In the lower end of the gorge of the Manaia Stream the slates have intruded into them massive dykes of igneous rocks, similar to those that appear on the coast-line between Waikawau and Mata Creeks, but, as all the dykes affecting this formation have appeared apparently during or after the deposit of the Kapanga group, they need not be particularly described in this place.