The biostratigraphy of the Lower Jurassic of the Stowell Park Borehole

The ammonite biostratigraphy of the Lower Jurassic of the Stowell
Park Borehole was originally compiled by L.F. Spath (1956) and
summarised in Green and Melville (1956). For the present report
it was considered impracticable to reidentify the nearly 5000
specimens used in these papers and also in Melville (1956) ~
Spath's ammonite nomenclature has been reinterpreted to update
the biozonation which is now based principally on Dean, Donovan
& Howarth (1961), Cope and others (1980), Ivimey-Cook & Donovan
(1983), Phelps (1985) and Howarth (1992). This updating has
included the use of the generic synonomy lists compiled by
Donovan, Callomon and Howarth (1981), and by revision of selected
specimens. The results of this review are given in Figures la and
lb which also shows, against a metricated graphic log of the
borehole, Spath's original zonation and this reinterpretation
with the ranges of many of the recorded generic taxa. This
revision supercedes the approximate zonal reinterpretation in
Ivimey-Cook (1971, Fig. 5). The ammonite biostratigraphy of the
British Sinemurian was also considered by Page (1992) who
proposed a number of ammonite correlated 'Horizons'.