Lower Cretaceous foraminifera from the Speeton clay of Yorkshire

• Main Author: Fletcher, Brian Norman
• Published: University of Hull 1966
• Subjects: 560; Geology
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.455603

One hundred and five species of foraminifera from the D, C and Lower B beds, representing the Berriasian, Valanginian, Hauterivian and lower Barremian stages of the Lower Cretaceous Speeton clays are described. The need for accurate localisation of samples resulted in a critical examination of the stratigraphy and lithology of these clays and the measurement of numerous temporary beach and cliff exposures. A detailed section of the C beds is given for the first time and Lamplugh's divisions of these beds are further subdivided. A new lithological section through the Cement beds is also described. The foraminifera from the D beds show that four faunal units can be recognised. The lowest beds are of Berriasian age, and the fauna is older than any Lower Cretaceous ones described from North-west Germany; the middle and upper D beds are Valanginian and correlate with the German succession Mittel Valendis 1 and 2 to Ober Valendis 3, whilst the uppermost few feet are of Hauterivian age. The C beds have a rich Hauterivian fauna comparable to beds of similar age elsewhere in Europe. On the basis of the foraminifera it is suggested that the basal 19 feet of the Lower B beds are of Hauterivian age whilst the remainder is Barremian. There is a marked similarity in the fauna of the Lower B beds with that in North-west Germany and Trinidad. The foraminifera from the Fordon Gl borehole has enabled a correlation to be made with the type section and confirms the suggestion by Neale (1960A) that the Hauterivian beds at Fordon are twice as thick as at the coast. The first occurrence of holothurian sclerites in the Lower Cretaceous of Britain is recorded and two new form species are described. Of the 105 species of foraminifera described 5 are new and 10 are left with open nomenclature. The stratigraphical distribution of the foraminifera is similar, but not identical, to that of Germany.