A 418kB, PDF File, this paper, the last unpublished element in vol 2 of my thesis, was a mature summation of all the stratigraphic work undertaken by me, between 1966 and 1979. It was never submitted for publication, but is now for its historic value. This is largely the original script, except for a slight updating of the
ovalis Subzone entry. There has been a recent spate of argument, regarding the identification of the 'lectotype' of Quenstedt's invalid trinomen
Ammonites sowerbyi ovalis, linked to a change in the name of the subzonal index species. This unfortunate situation has been rectified by ICZN 2005, OPINION 2123 (Case 999), where, amongst others,
Ammonites sowerbyi ovalis, Quenstedt, 1886; was placed on the Official List of Specific Names. The text has now been modified to take account of this 9/6/06.
Summary:
The lower boundary of the Bajocian Stage is discussed and the Aalenian accepted as a separate Stage. The Zones and Subzones of the Bajocian are briefly defined and their general synonymies given. The status of certain index species is discussed and type sections for the
garantiana and
subfurcatum Zones and the
romani and
banksi Subzones designated. The difficulties in applying this zonal scheme in the circum-Pacific area are briefly discussed and some indications of the stratigraphic importance of several rare, european Stephanoceratid species for World correlation given.
New Updated version, with page numbers and error corrections, uploaded 6th October 2006.
A 401Kb PDF file, this paper is
the last unpublished section of the whole thesis and was submitted in 1979, to the London Geological Society. I had the bad luck in having one referee, the same as for my 1976 Cotswold paper, who had a negative attitude towards any change in lithostratigraphic terminology, hated the Aalenian and had as a protégé D.C. Mudge; see
here for a copy of his comments and my response. They did not outright reject it, but demanded a level of change which was impossible at that time to implement (I could not afford to have it professionally re-typed!). Now thanks to OCR, it is eay to update.
The second referee was much more positive in his opinions, see here, for his comments and my response. All I will say here is that it was possible to almost completely re-affirm Buckman's interpretation of the age of the Cotswold beds, and that science appears to have moved back more than a century if we really believe that "the Inferior Oolite can be perfectly well subdivided on the basis of echinoids, brachiopods and probably several other groups as well": Oppel would turn in his grave!
This paper was produced to support the Geol. Soc Correlation charts, which finally appeared the next year, (1980). It contains an analysis of all the ammonites found in the Cotswolds up to that time and also contains a discussion of the South Cotswold, Mendip I.O., which L. Richardson got so very wrong. If nothing else, I hope that the publication of this here, will promote a greater interest in the problems presented by the latter district.
I have subsequently been able to update my knowledge of the the literature, whilst working as a volunteer at the British Museum (Natural History), using their extensive library services. It has thus come to my attention, that the now British Geological Survey, have published their own work on the Cotswold nomenclature (Barron, A.J.M., Sumbler, M.G. & Morigi, A.N. 1997, Proc. Geol. Ass., 106, pp. 269-285). However, they did in this work use many of my Member names, but in my opinion, unjustifiably, rejected my Formational names. They also, insisted on proposing to continue the existing tripartate division of the Inferior Oolite Group, by including the largely non marine Stanway Hill Formation herein, as a formal Harford Member within their Birdlip Limestone Formation. This, totally contrary to all established stratigraphic practices, thus combines two units with very different depositional environments and hence sedimentological characteristics. A reflection on the change in referrees for this style of paper me-thinks, what was frowned upon in 1975-9, is now accepted practice! I have modified this PDF to represent my updated views regarding these stratigraphic matters, based more closely on the original thesis edition, since these Formation and Member names were placed in the public domain, by their publication in the synonymy lists in this work.
A formal scheme of lithostratigraphic subdivisions for the Inferior Oolite ‘series’ is erected. The
Inferior Oolite Group of the mid-Cotswolds is defined as being made up of three Formations; the
Cheltenham, Hartley Hill and Stroud; with an additional fourth Formation (the Stanway Hill Formation, with Harford Sands and
Snowshill Clay Members), in the North Cotswolds. Three Members of the Hartley Hill Formation are re-defined or newly named;
the Lower-
Trigonia-grit, Windrush Valley and Notgrove Members; whilst the existing informal units, the
Clypeus-grit
and Upper-
Trigonia-grit are redefined as formal Members of the Stroud Formation. Bajocian ammonite
faunas from the Cotswolds are listed (+ 100 specimens) and analysed, whilst the correlation
of the Upper Bajocian rocks of the south Cotswolds is discussed and compared with the successions
in the Doulting and Dundry districts.
