Published online by Cambridge University Press: 01 May 2009
Changes in the Upper Cretaceous faunas of northeastern Ireland point to rising Cenomanian temperatures, and to progressive falls in temperatures from early Santonian to Maastrichtian times. At first sight, these changes fit the Cretaceous climatic trends claimed from isotopic data; but comparison with faunas seen in England suggests that this fit is illusory. It is suggested that faunas were more directly controlled by the influence of contrasting Atlanto-West Tethyan and Russo-Germanic water masses, and by changes in their relative distribution. Changes seen through the Irish Senonian may reflect the progressive submergence of a Scotland—Pennines barrier, permitting an increasing westward spread of the Russo—Germanic (‘boreal’) water and fauna.