Kaikoura Formation.
Te Anau Series—Hector (?).

Distribution—The principal mass of this formation extends southward from Big Bay and Martin Bay on the West Coast through the valleys of the Hollyford and Greenstone Rivers, and the Livingstone and Eyre Mountains to the Dome. From there it trends south-eastward across the Upper Waikaka to the Tapanui Mountains, and from there down the Lower Pomahaka and Clutha to Stony Creek. It is again found forming the northern base of Mount Misery and the hills north of the Tokomairiro River, between the plains and the sea. Another branch goes southward, forming the Takitimu Mountains, and then again divides into two, the westerly branch going through Black Mount and the Monowai and Howloko Lakes to the sea coast, between Te-wae-wae Bay and Chalky Inlet, while the eastern branch forms the Longwood Ranges, the Bluff [gap — reason: delete] and the northern part of Stewart Island, each of these being [gap — reason: delete]ted from one another by tertiary rocks or the sea. Wh[gap — reason: delete] this formation extends through Stewart Island I cannot say, [gap — reason: delete] have never been south of Port William.

In the north of the province these rocks are again found in the valley of the Ahuriri River, as far as the Waitaki, and they extend south through the Kurow Mountains. Another narrow patch occupies the hollow of the northern synchnal, and forms the southern part of the Kakanui Mountains, and the northern part of the Horse Ranges.

Rocks.—The rocks composing it are principally argillite, clay slate, and grey sandstone, or quartzite, with occasional beds of jasperoid-slates and conglomerate. In the Horse Ranges two bands of a very fine-grained granular marble are found, which is of a grey colour, with streaks of white running through it in all directions, and is of a subschistose structure. Port William, in Stewart Island is composed of slates and sandstone, dipping 70° W, and intersected by numerous dykes of syenite and granite. Rugged Island is principally quartzite, dipping 55° W. Codfish Island I did not visit, but the rocks brought me from there show that it is composed of quartzite, conglomerate, and phyllite. Dog Island is formed of slates and conglomerate, but I could not satisfy myself as to their dip.

Position of strata.—At the Bluff the rocks are more or less vertical, the dip changing from 75° N.N.E. to 85° S.S.W. At the Narrows, near Riverton, the beds are also vertical, with a S.E. strike. Between Lake Wakatipu and the Hollyford River the rocks of this formation, which commence just above the natural, bridge in the Route Burn, dip about 25° N.W. In the Leithen, which flows from the Umbrella Mountains into the Pomahaka, the dip is 35° S.E., and in the Upper Pomahaka 62° S.S.E.; in the Waipahi 75° S. At about three miles north-west of Clinton the dip is 25° S.S.W., and at Stony Creek 25° to 40° S.E. by E. In the northern part of the province I was not able to ascertain the dip in many localities, but at Mount St. Cuthbert it appears to be 40° N.W., and in the Horse Ranges it is 25° N.E. by E.

Relation to underlying formation.—That an unconformity exists between the Kaikoura and the Kakanui formations is evident from an inspection of the map. Along its western boundary the Kaikoura formation rests upon the Manipori formation, and wraps round it both at Martin Bay on the north and Preservation and Chalky Inlets on the south. At the Tapanui Mountains it overlaps the Kakanui formation, and rests partly on the Wanaka formation, while the patch of Kaikoura rocks in the Horse Ranges must also lie unconformably on the Kakanui formation, as there is not sufficient room for the whole of the latter to come out between the former and the Wanaka formation on the opposite side of the Shag Valley. It is not so easy to prove this in actual sections, but I believe that I came across a case of unconformity in the cutting leading down into the valley of the Pomahaka on the road from Dunrobin. The upper part of this cutting consists of argillites, page 36which I take to belong to the Kaikoura formation, and which, appear to dip 62° S.S.E.; but, as is usual in this formation, the bedding is not very distinct The lower part of the cutting is in phyllites, belonging undoubtedly to the Kakanui formation, and dipping 50° to 70° N.E., but the two portions of the cutting are divided by a space of more than 100 yards, along which no rocks can be seen.

Metamorphic Action.—Notwithstanding this unconformity, it it is by no means easy, in the absence of fossils, to draw the line between these two formations; for the metamorphic action has passed upwards through both, assimilating to some extent along their boundary the rocks of each formation. The gradual transition from true mica and chlorite schists to ordinary slate, or argillite, as we ascend from the Wanaka to the Kaikoura formations is certainly not due to any of the intermediate phyllites being "recomposed" rocks; but shows a gradual diminution in metamorphic action from below upward. The evidence here seems to me to be strongly against the views advocated by Sterry Hunt, Favre, and others, that the crystalline schists were originally deposited in their present form.

Thickness.—I have no data to estimate the thickness of this formation in Otago, but it is not so well developed as it is in the northern part of the South Island.

Age.—Notwithstanding that this formation is widely spread from one end of New Zealand to the other, no fossils have as yet been described from it, but it his always been considered as palæozoic both by Dr. Hochstetter and Dr. Hector, and as it underlies quite unconformably the Maitai formation, which is of lower jurassic or triassic age, we may consider it for the present as belonging to the carboniferous period, and the Kakanui and Wanaka formations to the upper and lower silurian periods respectively.

Fossils.—In my report on the geology of Southland I described some fossil remains from Coal Hill and Centre Hill as belonging probably to the Foraminifera,^* but I am indebted to my friend Professor Rupert Jones of the Staff College at Sandhurst, to whom I sent specimens, for correcting my mistake, and pointing out to me that they are weathered fragments of the shells of Inoceramus or Perna; consequently I have removed these rocks from the Kaikoura into the Maitai formation.

Minerals.—Gold in small quantities is found throughout this formation, but the Longwood Range is the only place in which it occurs to any considerable extent. The gold of the Orepuki district must have come out of these rocks, as it is found up the valley of the Waimeamea, a smill river rising in the Longwood Range. The conditions here are eminently favourable for the existence of metallic ores, as the slate rocks have been much penetrated by igneous dykes; and the same favourable conditions extend to the northern part of Stewart Island, and to the country between Te-wae-wae Bay and Preservation Inlet.

Nomenclature.—I consider the rocks here described to belong to the Kaikoura formation of my report on the geology of the northeast district of the South Island.^* They cannot be the same as the "Kaihiku series" of Dr. Hector,^† as neither the Kaihiku Mountain nor the valley of the Kaihiku River are composed of them. They may possibly belong to his "Te Anau series,"^‡ for in some respects his section agrees very well with their position; but if so, the name is unfortunately chosen as nearly as the whole of the shores of Lake Te Anau are formed either of gneiss belonging to the Manipori formation or of tertiary rocks. Dr. Hector also considers his "Te Anau series" as lower mesozoic, and compares it with the porphyritic rocks in South America,^§ to which the present formation does not bear the slightest resemblance. So that altogether I am unable to identify Dr. Hector’s "Te Anau series" with any rocks in Otago, and consequently I think it best that this formation, which is widely spread from Stewart Island to the North Cape, should go by the name of the Kaikoura formation until it is divided up more into detail.