Many workers consider the Cretaceous-Paleogene extinction the archetypal catastrophic pulse event caused solely by the Chicxulub bolide impact. However, based on a global scale analysis of marine animals, the Cretaceous-Paleogene boundary is a candidate for an extinction enhanced by the coincidence of press and pulse disturbances. We make a preliminary test of key predictions of the press-pulse hypothesis using palynological data. We document a local palynological extinction of 21% at the Cretaceous-Paleogene boundary, which is consistent with extinction rates of 15% to 30% at other localities in the Hell Creek type area and throughout North America. We also fi nd a decline in the number of dicot angiosperm pollen taxa between −3.5 m and −2.5 m below the boundary. We document a low-palynospecies-richness interval between −1.4 m and −1.0 m that includes extirpation, but not extinction, of some palynospecies. These changes in species richness are not correlated with changes in depositional style or pollen preservation, indicating that they may represent a biological rather than entirely taphonomic signal. Review and reanalysis of previously published data from other localities in the western interior of North America suggest similar declines in species richness within approximately the same stratigraphic interval. However, many of the species absent during the low-species-richness interval reappeared before the Cretaceous-Paleogene boundary, suggesting changes in community structure and composition before the terminal Cretaceous event-a key prediction of the press-pulse hypothesis-rather than gradual extinction in the latest Cretaceous.

Summary The Cockhill Marine Band of earliest Arnsbergian (E 2 ) age persists throughout the south-east quadrant of the Askrigg Block, and yields a large fauna, including the characteristic goniatite, Cravenoceras cowlingense; there is an increasing abundance of brachiopods towards the north. A new locality in the Mirk Fell Ironstone Series in Upper Swaledale yielding C. cowlingense is described. The Colsterdale Marine Beds of Arnsbergian age also persist throughout the area, two beds of shale being separated by the Colsterdale Limestone. The marine shales below the limestone vary locally in thickness, especially in the north where in Colsterdale thickening is accompanied by the appearance of a nuculid-gastropod fauna. Faunal characteristics of the marine beds are considered in terms of both lateral and chronological changes, and a case made out for a progressively deeper or more saline environment towards the southern margin of the Askrigg Block at the time of deposition of the upper part of the Colsterdale Marine Beds.

Summary Beds described range from the Sabdenian (H) to the Halifaxian (G 2 ) stage. The sequence is thinner stage for stage than in the Bradford area, with the most marked attenuation in R 2 . A shelly siltstone in R 1 , the Ure Shell Bed, and its associated shales yield a fauna rich in brachiopods. Above the persistent Brimham Grits are fifty feet of measures with two Lingula bands, thought to be the sole representatives of R 2 . Measures in G 1 and G 2 , include the Gastrioceras cumbriense band and two beds with Lingula. Some eight square miles of country hitherto mapped as Millstone Grit are considered to be of Westphalian age.