On the Relations of the Eocene and Oligocene Strata in the Hampshire Basin

Abstract

Conclusion The Lower Tongrian, as is well known, has no marine representative in the Paris basin, the great freshwater gypseous series occurring on this horizon; but in the small basin of the Cotentin, as M. G. Dollfus has so well shown, the Lower Tongrian or Brockenhurst series is represented by the “argile à Corbules”. The Headon series, including both the sands and overlying clays, contains a fauna which, by Hébert, Sandberger, Mayer, and other authors, has been recognized under the name of the zone of Cerithium concavum . The Brockenhurst series contains a fauna which has been quite as universally recognized as agreeing with that of the continental Tongrian or Lower Oligocene. Now, if my interpretation of the section be the true one, the beds containing the Tongrian fauna in the Hampshire basin overlie those containing the fauna of the zone of Cerithium concavum and this is the relation which is believed to exist between their continental representatives. Most geologists, indeed, group the zone of Cerithium concavum with the Upper Eocene or Bartonian, and the representatives of our Brockenhurst series with the Lower Oligocene. But, according to the views of Messrs. Keeping and Tawney, the beds which in this country contain the Lower Oligocene fauna form a thin and very inconstant bed in the midst of the strata containing the fossils of the zone of Cerithium concavum .