Simms, M.J., Chidlaw, N., Morton, N. & Page, K.N. 2004. British Lower Jurassic Stratigraphy. Geological Conservation Review Series, No. 30, Joint Nature Conservation Committee, Peterborough, ISBN 1 86 107 495 6. The original source material for these web pages has been made available by the JNCC under the Open Government Licence 3.0. Full details in the JNCC Open Data Policy

Tables

(Table 1.1) Brachiopod biozonal scheme for the Lower Jurassic Series of Great Britain. After Ager (1978, 1990).

Chronostratigraphy Brachiopod Biozones Ammonite zone equivalents
Upper Toarcian none
Lower Toarcian Stolmorhynchia (?) bouchardii Nannirhynchia pygmaea Serpentinum–Bifrons Tenuicostatum
Pliensbachian Prionorhynchia serrata Homoeorhynchia acuta Gibbirhynchia curviceps Spinatum

Spinatum

Jamesoni–Margaritatus
Sinemurian Cuneirhynchia oxynoti Piarorhynchia juvetzsis Semicostatum–Raricostatum Semicostatum
Hettangian Cakirhynchia calcaria Planorbis–Bucklandi

(Table 1.2) Terebratulid stratigraphical distribution in the Lower Jurassic Series of Great Britain. After Ager (1990).

Chronostratigraphy Terebratulid Biozones
Upper Toarcian Lobothyris haresfieldensis Zeilleria lycetti
Lower Toarcian Orthotoma globulina
Upper Pliensbachian Zeilleria quadrifida Aulacothyris resupinata Lobothyris punctata
Lower Pliensbachian Cincta numisynalis Zeilleria darwini
Upper Sinemurian Cincta cor
Lower Sinemurian Zeilleria vicinalls
Hettangian Zeilleria perforata

(Table 2.1) Table of approximate zone/subzone-pair thicknesses for the Hettangian and basal Sinemurian stages at six different locations. (* = figures estimated from total zone thickness.) Data from Cope et al. (1980a), Warrington and lvimey-Cook (1995) and Page (1992, unpublished Geological Society Correlation Guide).

Ammonite zones/ subzone pairs Somerset coast South Wales (offshore facies) Devon–Dorset coast Stowell Park Borehole Mochras Borehole Radstock shelf
Bucklandi–Lyra 90 ? 4 35 c. 90* 0
Conybeari–Rotiforme 47 c. 35* 6 18 c. 70* 0
Angulata 40 30 5 17 60 0
Liasicus 27 30 /

4

 18 59 0.5
Planorbis 8 9 4 11 18 2.5

References