. Bulletin of the British Museum (Natural History), Geology. 2. The Anglian Trough In this area the base of the Lower Chalk is represented by the Cambridge Greensand (Hart 1973a). Detailed microfaunal analysis has shown that the age of the Cambridge Greensand is upper Zone 8 (uppermost Hypoturrilites carcitanensis Assemblage Zone of Kennedy 1969), even though the only dateable macrofaunal elements are from the dispar Zone. The underlying Gault Clay belongs, on microfaunal grounds, to the Arrhaphoceras substuderi Subzone of the dispar Zone. This shows that the upper part of the dispar Zone is n
. Bulletin of the British Museum (Natural History), Geology. 2. The Anglian Trough In this area the base of the Lower Chalk is represented by the Cambridge Greensand (Hart 1973a). Detailed microfaunal analysis has shown that the age of the Cambridge Greensand is upper Zone 8 (uppermost Hypoturrilites carcitanensis Assemblage Zone of Kennedy 1969), even though the only dateable macrofaunal elements are from the dispar Zone. The underlying Gault Clay belongs, on microfaunal grounds, to the Arrhaphoceras substuderi Subzone of the dispar Zone. This shows that the upper part of the dispar Zone is not represented in this part of Cambridgeshire, even LIDDINGTON-WILTS (M4 Borehole # 179) SU. 217 804 12 R 1-2-3-4-8-11-12-13-15 A. 21-24-28-30-33-35 C. 34-37-47-50 R 1-2-3-4 -11-12-13 -15 A. 21-24-28-30-33-35 C. 37-47-50 R 1-2-3-11-12 A. 21-24-28-30-33-35 C. 37-45-47-50 Totternhoe Stone R 1-2-3-11-12 A. 21-24-28-30-33-35 C. 37-45-47-50 ^VvJ 100. Fig. 20 Microfaunal details, Liddington Borehole, Wiltshire. The ornament used in the planktonic/ benthonic ratio graph is explained on Fig. 12c. The species lists are in three categories (P. - planktonic, A. - agglutinated benthonic and C. - calcareous benthonic), the numbers referring to the species listed on the range chart (Fig. 9).The black dots indicate sample positions in all vert- ical Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original British Museum (Natural History). London : BM(NH)
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