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the condition of the " sandstone "of the miner. On the eastern side of the range the exact nature of the rocks on this line of section are to be inferred from what can be seen on the line of travel from Coromandel to Kuaotunu, on which it is evident that the rocks are much less decomposed and are at places intensely dark augitic andesites. Quartz-reefs appear towards the eastern end of the section, and towards the west are numerous near the contact of the volcanic rocks with the slates and in the slates themselves. The dip of the rocks is generally to the eastward, at low or moderate angles. The next section, from the north-west side of Preece's Point, is taken along a line running east-south-east across the Waiau Flat, the narrow strip of the Kapanga rocks at the foot of the Tiki Spur, and the slate country within the Maitawai Valley, to the middle slope of Castle Rock Range, where it enters a country formed of rocks belonging to the group being described. On the eastern slope of the range the rocks are similar to those occurring along the line of section last described, but on the crest of the range the great dyke constituting Castle Rock crosses the line, and on the eastern slope, in very broken and rugged country, the rocks change to a darker tint and are largely ash-beds, part of which are solidly compacted beds that can be well studied on the road that from the Waiau Saddle, by way o£ the Waitakatanga Valley, and that by which the Mahakirau River leads to Mercury Bay. On the east side of the range the rocks sometimes resemble those of the Kapanga group, and the opinion might be hazarded that at places these rocks are present; but such doubtful rocks are every here and there seen to be associated with the typical rocks of this group, which latter as the section is followed to the eastward becomes more and more pronounced, and, finally, for the last two miles of their exposure, there can be no doubt as to which group of rocks they should be referred. Finally, the Thames-Tokatea rocks are overlain unconformably by strata containing coal or lignite, and volcanic rocks belonging to the Beeson's Island group. Mining in the neighbourhood of this line of section is carried on within the Maitawai watershed, on the east slope of the Castle Rock Range, and for the most part in the lower part of the Thames-Tokatea group. The Manaia Section, which from its western extremity on the Peninsula between Coromandel and Manaia Harbours is continued east-south-east across Cape Colville Peninsula, shows the presence of the Thames-Tokatea group within the Manaia watershed. Near Hooker's Store, in the Mahakirau Valley, and thence following the valley of that river upwards for some miles, the rocks are seen to be distinctly such as are here regarded as typical of the group to which they belong. In the Manaia watershed nothing is known as to the lower part of these Thames-Tokatea, rocks, but they cannot be greatly different to what appears in the Castle Rock Range, and the range immediately south of the Mercury Bay Road. The greater part of this line of section shows the presence of rocks other than those of the Thames-Tokatea group. Contiguous to the line, there is in the Mahakirau Valley one very large reef, and several of lesser size, on which mining was being carried on during the past summer. To the southward the next section runs generally along the line of the southern boundary of Coromandel County. Along this the rocks of the Thames-Tokatea group have expanded so as to cover a greater breadth of country than they do at any point to the north or to the south within the Thames-Coromandel area. In Camelback Mountain it attains its highest elevation above the sea, and constitutes exceeding rugged country on both slopes of the range. On the higher part of the range the rudely stratified volcanic material seems to have a nearly horizontal arrangement. In the Waikawau Valley the section was followed east as far as the slates extend, but not further, and thus the exact nature of the rocks forming the higher part of the main range was not determined. In the Waiwawa Valley the north-west branches of the river drain the country along this line of section. As on passing the coarse breccias of the -Beeson's Island group, seen in the Waiwawa Valley, the next rocks to the westward resemble those of the Thames-Tokatea group, and are continued south along the main range to the sources of the Puru and Tararu Creeks, there can be little doubt that the rocks of the main water-divide and the spur-range to the south belong to the division of the volcanic series. In the valleys of the Mata River and Tapu Creek, the lowest beds of the Thames-Tokatea group are rather coarse breccias, followed by the grey tufaceous sandstone of the miners, which mantle over the slate and appear both on the coast-line and inland sides of the range. In the south-west tributaries of the Waiwawa the higher part of the range shows heavy floes of dark andesite, underlain by fine-grained breccias beds; and on the lower slopes of the range, descending into the deep valley of the southern branch of the Waiwawa, grey tufaceous sandstone, often charged with mineral sulphides, and nests and small leaders of quartz, form the rocks on the west side of the Waiwawa watershed. In the section which, from the shore of the Firth of Thames, follows the general trend of Tararu Creek into the south-east sources of the Puru, crosses the main range between the principal sources of that stream into the upper Waiwawa Valley, and thence is continued across Table Mountain Range to Boat Harbour on the east coast of the Peninsula, to the westward the first rocks met with are the Tararu breccias, lying at the base of the Thames-Tokatea group and resting on the felsite tuff of Rocky Point. This is the position of the breccias as seen in the section from Rocky Point south along the shore-line, and that which the similar or identical rocks occupy at Tapu Creek and in the Mata Valley. They are traceable but for a short distance up Tararu Creek, being followed and overlain by the auriferous rocks of the Thames Goldfield. In following up Tararu Creek to the saddle overlooking the head-waters of the Puru Stream alternations of tufaceous sandstones, undecomposed crystalline rocks, and breccias of finer grain than the Tararu breccias are frequent, three distinct bands of breccia rock being passed over before reaching the main ridge. The whole system as exposed along this line dips to the eastward, and therefore, generally, the lower down the spurs in the direction of the shore of the gulf the deeper-seated are the rocks met with. Round the sources of the Puru other breccias again occur, and forming the peaks of the range are heavy floes of augitic andesite. On the slope of the deep valley between the main range and