the Eocene coal-measures is doubtful; but, in any case, the interval of time represented is long. The general evident discordance in strike and dip, together with the great difference in lithological characters between the Palaeozoic and the early Tertiary rocks, renders recognition of the unconformity an easy matter. Probably–in fact, certainly—some deposition of sediments took place between the Ordovician and the Eocene in the North Westland and Westport districts; but of this there is no direct evidence, all traces of such beds having been removed by pre-Eocene erosion. At Reefton, however, near the districts discussed, Devonian strata are found, and Trias-Jura rocks appear on the eastern side of the Southern Alps. It is noteworthy that though over considerable areas the bituminous-coal measures were deposited on a nearly flat surface, yet in places the overlap of the higher beds on the pre-Tertiary old land is considerable. The nature of the basal conglomerate, and more especially of the Hawk's Crag breccia, is further evidence of an irregular land-surface at the beginning of the Eocene. Although the Kaiata beds, the uppermost member of the bituminous-coal measures, have nowhere been observed to thin out owing to overlap, yet in many places Eocene strata are absent, and Miocene beds are found resting on pre-Tertiary rocks. The question of whether this increased extent of the pre-Eocene unconformity is due wholly to overlap, or in part to erosion of the bituminous-coal measures, has already been discussed, and decided in favour of the latter supposition. Summary and Conclusions. The evidence of unconformity at two horizons, one pre-Tertiary and the other post-Miocene, is clear and unmistakable. In the case of a third unconformity—that between the Eocene and the Miocene—certainty is wanting, but the available data strongly favour a stratigraphical break. In view of the importance of the matter from an economic point of view, it may be as well roughly to summarize the evidence both for and against this pre-Miocene unconformity, and to leave the reader either to form his own conclusion or, if he pleases, to preserve an open mind. Unconformity is supported by the occurrence in Miocene rocks of water-worn pebbles of coal and of carbonaceous shale almost certainly derived from Eocene coal-measures; by marked discordance of dip between Miocene strata and Hawk's Crag breccia at Brighton; by a number of apparently unconform-able contacts between Eocene and Miocene strata; and by the strong overlap of the Miocene rocks on the pre-Tertiary land-surface. On the other hand, it is just possible that the coal pebbles are a product of contemporaneous erosion; that the discordance in dip between Miocene and Eocene rocks at Brighton has another explanation; that the apparently unconformable contacts between Eocene and Miocene strata can be explained by faulting or in some other way; and that the strong overlap of the Oamaru rocks on the pre-Tertiary land-surface is wholly due to the bold relief of the land at the beginning of the Eocene, and not at all to unconformity between two Tertiary formations. Though the evidence for a stratigraphical break may not be regarded as conclusive, it is mainly of a positive character, whilst the opposing evidence is largely negative. It is practically certain that considerable earth-movements took place after the formation of the bituminous-coal seams and before the deposition of the Oamaru series. The point in doubt