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General Geology. ' r The geology of the portion of New Zealand between Waitara and Te Kuiti shows much variety. Briefly put, the geological column may be summarized as follows : — !3. Argillites and grauwackes. Sedimentary 2. Conglomerates, claystones, sandstones (with coal-seams), and limestones. (l. Black-sand beds. 1 3. Serpentines. Igneous - 2. Rhyolitic tufa and breccia. il. Andesitic tufa and breccia. The oldest sedimentary rocks (No. 3 above) are seen on the Awakino - Te Kuiti Road a few miles east of Awakino, and again" in many places underlying the later sedimentary rocks (No. 2 above) in the low rolling country around Paemako and Piopio. They are well exposed at the Wairere Falls, where they contain small stringers of quartz. From an economic standpoint the rocks of this series are unimportant in the locality under description. They are pre-Tertiary in age (possibly Triassic), and wherever exposed are much altered, and exhibit a complicated structure. The sedimentary rocks of No. 2 series above cover by far the greater part of the area under description, and are of commercial interest, since they contain (1) extensive coal-seams ; (2) thick beds of limestone suitable for cement and lime manufacture, and clays suitable for brickmaking and for cementmanufacture ; (3) supposed reservoirs or pools of petroleum. These three headings will be discussed in a later part of this report. The rocks of this series (No. 2 above), which are in general quite unaltered, have been classified by the earlier geologists, partly as Cretaceo-Tertiary and partly as Pliocene. The writer's visit was not of sufficient duration to make a definite decision on this question of age, but he is of the opinion that the whole series belongs to the Tertiary period, and is probably mainly Miocene. The structure of the Tertiary rocks is of interest, since this feature has such a marked influence upon the presence or absence of petroleum. As far south as rocks of this series appear unshrouded by volcanic debris —near Waitara ; up the Mokau to and beyond the outcrop of coal at the rapids, twentythree miles from the mouth ; up the coast as far north as Pet one Creek ; and along the Awakino Te Kuiti Road as faT as Mr. A. .). BignelPs house (five miles and a half north-east of the mouth of the Awakino) the Tertiary beds dip at very gentle angles, or arc disposed almost horizontally. The structure seems in general to be that of a westerly- or south-westerly-dipping monocline. The smaller irregularities of structure in this monocline —gentle anticlinal and synclinal cross-swells —produce, however, slight changes in dip, sufficient, it is thought, to influence the location of the petroleum-pools, if these exist. Along the coast in the neighbourhood of Petone Creek and northward the Tertiary rocks are greatly corrugated and faulted. On the Awakino -Te Kuiti Road, north-eastward from Bignell's, the strata also exhibit marked complications, being in places both folded and faulted. The various formations composing the series are apparently repeated several times between Bignell's and Te Kuiti. In this part of the area being described the series is known in places not to be of great thickness owing to the widespread exposure of the earlier sedimentaries. Thus, at the Wairere Falls, limestone, which forms one of the upper terrains of the series, immediately overlies the older sedimentaries, and oyer most of the rolling country around Piopio and Paemako Tertiary rocks occur only as outliers overlying the pre-Tertiaries. The coal-seams interstratified with sandstones and claystones lie towards the base of the series. In the seaward and more southerly part of the area under description the limestones are overlain by many hundreds of feet of claystone (locally called " papa ") and sandstone ; but these upper rocks are less conspicuous inland. A splendid section of the upper measures is visible at the White Cliffs, overlain by later volcanics. The black sands (No. 1 above) are seen in several places along the coast. Their black colouring is due to the presence of magnetite and ilmenite (titanic-iron oxide). The beds all contain more or less of these minerals, and in some places are of considerable thickness, but elsewhere they are much intermixed with quartz sand, titanite, and other materials. The beds of fairly pure black sand are generally thin and lensoid, being replaced both in horizontal and vertical extension by more barren sandy material. Frequently the outcrop of these black-sand beds is rusty, owing to the further oxidation of the iron-bearing minerals they contain. The beds are generally soft and friable, excepting where held together by hydrous ferric oxide, and are usually disposed horizontally, but in places exhibit false bedding. They are thought to be Pleistocene in age, but probably their deposition extended from that period to the present. Reassortment of the sands by the winds and the sea-waves is constantly proceeding, and thus are separated from the lighter material heaps of rich black sands containing hundreds of tons of high-grade material, which in the future, with exhaustion of other iron-ores more easily treated metallurgically, will be of great value. They are especially conspicuous in the neighbourhood of the sand-dunes just north of the mouth of the Awakino River. The igneous rocks in this paper, which, owing to their economic importance, deals principally with the Tertiary sedimentaries, need be mentioned but briefly. Serpentine rocks, which from a microscopic examination were found to be highly altered peridotites (apparently, in part at least, harzbergite), occur in a narrow band running N. 20° E., and outcropping beneath Tertiary limestones on Rangikohora Creek —a tributary of the Mokau, and about two miles south-east of the Wairere Falls. The serpentines are thought, from the doubtful analogy of similar rocks in the neighbourhood of the North Cape, to cut the supposed Triassic rocks,

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