This system is found in the North Island between Kawhia and the Waíkato, and again at Port Waíkato (Putatáka Scries) ^§. It also occurs at Wellington, in the Ruahine range, and again in the Raukamára range, near the East Cape. In the South Island it is found on the eastern side of the ge-anticline, outside the Maítai rocks, and occupies part of the synclines, b, c, and d, already mentioned (fig. 1), as well as the Southland syncline (g). In Westland and in the north-west of the Nelson Province it is quite unknown. A small patch is found near Nelson (Wairóa Series), but the two largest areas covered by this system are on the northeast and on the south of the island. Commencing in the neighbourhood of Kaikoura peninsula, it skirts the main range to the Hanmer plains, sending northwards a long tongue towards the Wairau gorge. To the south it reaches the Canterbury Plains at the gorge of the Ashley. It reappears in the Malvern Hills, and in the north branch of the river Ashburton, whence it runs southwards to the neighbourhood of Mt. Peel, extending inland through the Clent Hills and Rangitáta River as far as the junction of the Clyde and the Havelock, near Mt. Potts. Another exposure of these rocks occurs somewhere near the Mackenzie Plains, in the centre of the basin formed by the main anticline and its easterly extension in Otago (a, a, fig. 1), and the secondary anticline (e) running from Hunters Hills towards Mt. Cook. Mr. A. McKay has proved the existence of this exposure by finding fossils be- page 203 longing to the system in boulders in the Waítaki ^*; but the rocks have not yet been detected in situ. The southern development of the system is on the coast between the rivers Clutha and Mataúra, passing inland through the Hokanúi Mountains to beyond Mt. Hamilton. This is the best locality for making out the scries of rocks forming the system, a work which has been ably accomplished by Mr. S. H. Cox^†.

This system is undoubtedly unconformable to the Maítai System, but it not easy to get good sections to prove this. The best is perhaps in Southland, at the Takitimú Mts., where I reported an unconformity in 1872 ^‡, and this has since been confirmed by Mr. Cox ^§ (fig. 3, e). In no place, however, is it known to rest on the Maítai System.

The Hokanúi System forms the upper part of Dr. von Haast's "Mt. Torlesse formation." It has been divided into a considerable number of series, all conformable to each other, but distinguished by their fossils. The fossils, however, have not been described; and, although it may very probably be true that all these series will be found to be necessary, at present it is impossible to recognize them in the field, and it therefore seems to me preferable to reduce the series to three at the most. The Kaihíku, Series forms the base of the system; but fossils are rare, and I doubt much whether it can page 204 be separated from the Wairóa Series. The only characteristic fossil mentioned by Dr. Hector is Trigonotreta undulata. Labyrinthodont teeth and Glossopteris are found both here and in the next higher series. Remains of what appears to be an Ichthyosaurus^* have been found near Mt. Potts, in S. Canterbury, in beds recognized by the Geological Survey as belonging to the Kaihíku Series. Dr. Hector considers this series of Permian age; at the same time he notices the absence of "the usual Palæozoic elements of a Permian fauna," and, I may add, of a Permian flora also.

The Wairóa Series is well characterized by the following:—

• Belemnites (?) otapiriensis, Hector.
• Monotis salinaria, var. richmondiana,
• Zittel.
• Halobia Lommelli, Wissm.
• Mytilua problematicus, Zittel.
• Spirigera Wreyi, Suess.