positive evidence. Rudistids, reef corals (Squires, 1958), large Foraminifera, and other tropical forms are absent, but beds of the shelf facies in which they would be likely to occur are not represented in the middle and lower Cretaceous of the northern part of New Zealand. On the other hand the climate is unlikely to have been much cooler than at present, at least for parts of the Cretaceous, as saurian bones occur in the Motuan (Cenomanian) of the North Island and are relatively abundant in the shelf facies of the Haumurian (Maestrichtian) in the South Island. The Cretaceous floras provide little climatic information. Cycads are known from the Coverian and Ngaterian (McQueen, 1956), and Araucarias with well defined annual rings in sub-Piripauan freshwater beds (Stopes, 1914). The plants are from the South Island and the climate may have been slightly warmer then than it is now. The non-marine beds of the west coast of the South Island present more problems than they solve. The red colour of the conspicuous breccias of the lower and middle Cretaceous has often been discussed but never satisfactorily explained (see Gage, 1952). It is probably a climatic indicator. The rock fragments are fresh and the red colour cannot be due to tropical or sub-tropical lateritic weathering. They have been superficially oxidised, and are red only where carbonaceous material that acts as a reducing agent is absent. Surface conditions would favour oxidisation only if plant cover was scanty or absent. This could have been caused either by cold or Fig. 14.—Sketch cross-section through the Motu Falls section. Stage symbols as on map. Length of section about 18,000ft. Horizontal and vertical scales are the same. by aridity, perhaps only seasonal. In the absence of evidence for cold conditions aridity would seem to be the more likely cause, but independent evidence is required. No glacial beds are known in the New Zealand Cretaceous. The virtual absence of limestone except in the Teurian (Danian) is a peculiar feature of the New Zealand Cretaceous. Limestones do occur, but they are either only a few inches thick and composed entirely of Inoceramus fragments, as in the Motuan, or so impure as to be better described as calcareous sandstone or mudstone. Limestones are known from the cold as well as from warm stages of the New Zealand Tertiary and Pleistocene, and their absence from the Cretaceous may not be due to climatic factors. Diastrophism, Sedimentation, and Igneous Activity Cretaceous Diastrophism In 1950 the writer presented a chart showing important Cretaceous sections set out to show the evidence for dating the unconformity that was considered to separate the Cretaceous from earlier rocks. The marine and non-marine Cretaceous sections are better known than they were in 1950, and the evidence for dating unconform-