I. A suggested revision of the Cenozoic scale
BERGGREN (1969) has suggested a substantial revision of some of the boundaries of the Cenozoic (Table 1), based on revised definitions and correlations of some of the dated stratigraphical divisions, and on as yet unpublished K-Ar ages. The suggested revisions are most substantial in the Miocene, which has both of its boundaries reduced in age.
2. New data relating to the Mesozoic
Further data on the Cretaceous-Tertiary boundary has been secured and published by Folinsbee, Baadsgaard, Cumming, Nascimbene & Shafiqullah (1966). This paper on the ages of Western Canadian bentonites was published after the paper by Shafiqullah et al. (1968) was written, but before the latter was published: the 1966 paper was not available to the author. It contains new data on the age of the Upper Cretaceous and presents revised figures for many of the uppermost Cretaceous bentonites quoted by Shafiqullah and others (1968). The data are given in the following abstract (Item 365) which supersedes Items 363 and 364, but not Item 362, and invalidates some details of Fig. 2 in the preceding article. The conclusions of Folinsbee et al. (1966) are:
- (i) the Bearpaw Formation, correlated with the Upper Campanian of Europe by use of Acanthoscaphites, and by use of microfaunas with Upper Cretaceous strata elsewhere in North America, was formed in a transgressive sea from 73 to 68 m.y. ago and in a regressive sea from 68 to 66 m.y. ago; and
- (ii) that sanidine ages from three
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This 250-word extract was created in the absence of an abstract.
