that Woods's specimen differs from true sacya and is very close to subsacya Marshall from a higher horizon. Considering all these points, and the faunas of the overlying Piripauan, we now suggest that the four divisions of the Clarentian outlined may be tentatively regarded as covering the period Albian to Coniacian. It is of interest that Belemnites superstes Woods is known only from the lower part of the Clarentian, and this species has been placed by Whitehouse (1924, p. 412) in Dimitobelus, known in Australia only from the Upper Albian. Piripauan. The Piripauan at its type locality (“beds at Amuri Bluff below the Teredo limestone”—Thomson, 1917, p. 409) consists of the following units:—basal sandstone with calcareous bands containing Mollusca, “sulphur sands,” black grit with shark teeth, and concretionary glauconitic sandstone (“saurian beds”). A detailed account has been given (Thomson, 1920, p. 341) of a similar succession in the not far distant Middle Waipara area, where basal coal-measures and Ostrea beds are followed by “saurian beds” and then by Waipara greensand; the occurrence of Cimoliosaurus australis (Owen) in the two latter, and of Pacitrigonia Marw. and Conchothyra Hutt. in the former, confirms the association with the type Piripauan. This is mentioned, since good micro-faunas have been obtained from the Mid-Waipara, but not as yet from Amuri Bluff. The Piripauan cannot be divided into several Cretaceous stages as conveniently as the Clarentian. It is only about 1000 feet thick and possibly covers a much shorter period of time. Most of its important Mollusca come from the basal beds, while Foraminifera are known only from the top of the “saurian beds” and basal Waipara greensands. Although the Clarentian and Piripauan are nowhere known to be in contact, the presence of different Inocerami in each, and the absence of any faunal agreement between the topmost Clarentian and any part of the Piripauan indicates that the two systems do not overlap. The characteristic Belemnite of the basal Piripauan, B. lindsayi Hector, has been made by Whitehouse (1924, p. 414) the monotype of Cheirobelus, as distinct from the Clarentian Dimitobelus; in the absence of related forms he accepted for it Woods's determination of a Senonian age. The characteristic Inocerami of the Piripauan are australis and pacificus, both of Woods, but Heinz's work (1928) on these is somewhat contradictory. They occur together in the basal conglomerate, and black grit, and are certainly younger than the Clarentian forms, yet Heinz divided them into four different species, characterising four horizons from Cenomanian to Lower Emmscherian. Two other molluscan genera are of importance. Pacitrigonia Marwick (1932, p. 505) is a group apparently confined to the Upper Senonian of the Southern Hemisphere, while Conchothyra Hutton (see Finlay and Marwick, 1937, p. 64) has no outside close relatives, is limited in its type species to the Piripauan, but extends as another species to the Danian Wangaloan.