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hard bluish rock, probably dipping to the east, is seen in a road-cutting. Mudstones seem to overlie. lhe country to the southward of the Tenui—Whakataki Road between Castlepoint and lea Homestead consists mainly of sandstones, with minor bands of claystone and fine conglomerate. These rocks, though most commonly dipping to the west, often dip in other directions. Loose boulders seen in a tributary of Otahome Stream are calcareous, and some show the remains of a lather problematical organism with a fibrous or prismatic structure. The rugged prominent bluff known as Castle Hock, and the island that forms the seaward side of Castlepoint Basin, arc according to McKay, of fossiliferous rocks corresponding in age to those at Napier. Park maps them as Miocene. In 1875 McKay found in a stream that he calls Station Creek (perhaps the Ngakauau of the present maps) a boulder of an igneous rock containing leucite.* The source of this rock has never been determined. Northward of Whakataki only the i ocks exposed along and near the coast were seen. Near the mouth of the Whakataki Stream, and northward for some miles, the rocks are well-bedded sandstones, with minor mudstone layers. These in general etrike parallel to the trend of the coast, and dip 20° to 45° or more to the west. In places, however, the strike is seen to curve round in a very short distance, owing to what may be called very pronounced " rolls.' . Occasionally the dip may approach 90°. At Reef Point, about four miles south of the Mataikona River, the rocks exposed are much altered, and are jointed and shattered very irregularly. These rocks, which might be called grauwackes, are decidedly old-looking, and i|uite possibly are pre-Cretaoeoue in age. The dip seems to be at a high angle to the south-west. On the south side of the Mataikona River, near Mr. Barton's homestead, the rocks are of somewhat similar character, but are finergrained, and contain dark mudstone or shale bands, with some carbonaceous material. The dip of these rocks may be at a high angle to the east. In Pakowai Creek, a tributary of the Mataikona. the chief rocks exposed are said to be sandstones with a westerly dip. Towards the head of the Mataikona River rocks corresponding to those of the Rimutaka Range are reported. Pebbles seen in the bed of the river support this statement. At the mouth of the Mataikona and northward bands of medium-grained conglomerate are seen along the beach, interstratified with sandstones and mudstones. Farther north the conglomerates are no longer seen, but well-stratified alternating sandstones and mudstones are still exposed along the beach. The strike, while in general parallel to the ooast-line, varies greatly. The dip is as a rule westerly at angles of 45° or more. In some places it flattens, in others it may approach 1)0°. On the road from Aohanga Landing over the ridge to Aohanga Settlement two or three outcrops of shattered mudstones or shale are seen. Near the top of the ridge, about 300 ft. above sea-level, a bold mass of glauconitic sand+itoue, that lias been quarried to some extent for roadmetal, appears on the east side of the road. The outcrop is about a chain long from east to west, and about half a chain wide. It weathers to a green colour, and is much jointed and altered. No strike or dip could be obtained. The solid sandstone when broken, and the loose pieces of stone in the quarry, possess the remarkable property of smelling strongly <>f kerosene, t The hard rocks that outcrop on the north and south banks of the Aohanga River near its mouth are said to consist of the same sandstone, but the} - have not as yet been found to contain petroleum. A short distance up the Aohanga River from the hotel altered sandstones with shaly bands may be seen on both sides of the river. These rocks dip inland, and are followed in that direction by what appears from a distance to be a bluish mudstone. Some six miles up the river a fossiliferous limestone appears. This may possibly be of Miocene age. As regards the age of the rocks along the coast-line from Whakataki to Aohanga the writer agrees with McKay and Park in considering them pre-Tertiary. In the absence of recognizable fossils their exact age must remain uncertain until a detailed survey of the region has been made. Structure. Viewed broadly, the whole area from the east coast to the Wairarapa Valley appears to be monocline, with dip to the west. Thus the older rocks are to the east, the younger to the west (except at Castlepoint). Eastward of the " taipos " the -strike and the dip of the rocks are often very irregular. An anticline is stated by Park to cross the Whareama River near lea, and elsewhere there seems to be minor anticlines and synclines. More especially just east of Tenui there is some evidence of an anticline. On the eastern side of the various "taipos " the country is almost everywhere broken by faults. In the Whakataki Valley, at Castlepoint, at Reef Rock, at Mount Percy, and north of the Mataikona River faulting is very prominent. Economic Geology. Petroleum. —The main object of the writer's visit to the east Wairarapa district was to obtain evidence of the existence of petroleum. The most direct evidence bearing on the subject is the occurrence, as previously mentioned, of petroliferous glauconitic sandstone near Aohanga. This rock, according to a test made in the Dominion Laboratory of a sample supplied by Mr. D. Laing, contains ()'4(! per cent, of petroleum. This result does not include any oil of the benzine class that may have been present. As evidence of the strong petroleum-like smell of the rock, it may be mentioned that according In reliable reports horses used to shy when passing over portions of the road freshly metalled with the rock.

* Mines Report, 1889, C.-9, p. 36. tMr. H. Hill mentions this occurrence in the paper previously mentioned. (See Trans. N.Z. Inst., Vol. xxxix, 1906, pp. 512, 516.)

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