peter franklin rawson, dennis curry, frank charles dilley, john michael ...

Simbirskites (Speetoniceras) inversusT . Endemoceras regaleLower Hauterivian „ .Endemoceras noricumEndemoceras amblygoniumThe Lower/Upper Hauterivian boundary follows Thieuloy’s (1973) correlations.The zonation compares closely with the German scheme put forward by Kemper(1973a) and slightly modified by Kemper et al. (1974: see also Rawson 1974): theEndemoceras (= Lyticoceras auctt.) zones are based partly on the work of Thiermann(1963).The BarremianBarreme and Angles (Basses-Alpes, France) were both mentioned in Coquand’s(1861) original designation of the stage, but Busnardo (1965) has now designatedthe Angles roadside section as the stratotype. This section is almost continuous,completely visible, easily accessible and yields a good ammonite fauna. Busnardo(1965) amended the established zonal scheme but retained a bipartite division intothe Nicklesia pulchella Zone below and the Silesites seranonis Zone above.Heteromorph ammonites of the family Ancyloceratidae are common in both theFrench (Tethyan) and north-west European (‘boreal’) faunas, but faunal similaritiesbetween the two areas have been regarded as superficial (e.g. Spath 1924) andtaxonomy has diverged accordingly (e.g. Koenen 1902; Sarkar 1955). There is nowevidence of elements common to England and south-east France (Rawson 1975a)but at present the poorly known English faunas can be compared only with thenorth German sequence, where the Barremian is currently divided into zones basedon Koenen’s and Stolley’s work, as follows:Parancyloceras bidentatumHemicrioceras rude‘Crioceras' sparsicostataParacrioceras denckmanniParacrioceras elegansHoplocrioceras fissicostatumParacrioceras rarocinctumIn England, Barremian ammonites occur in the Speeton and Snettisham Clays, butonly at Speeton is the bulk of the stage represented. Even here exposures areindifferent (see p. 31) and the stratigraphical relationships of isolated sections aredifficult to establish. Spath’s (1924, p. 78) identification of museum specimenssuggested that faunas of most of the German zones occur at Speeton, and Spathadopted the German zonation for this sequence. However, the horizon of mostspecimens is not known and few zonal divisions can actually be established in thefield. Most of the crioceratitids occur as flattened calcareous films, and threedimensionalforms are rare and fragmentary. Thus only three zones, one composite,