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The and of the (Upper 1 to Upper ) at Scratchell’s Bay and , , UK. 2 3 Peter Hopson1*, Andrew Farrant1, Ian Wilkinson1, Mark Woods1 , Sev Kender1 4 2 5 and Sofie Jehle , 6 7 1 British Geological Survey, Sir Kingsley Dunham Centre, Nottingham, NG12 8 5GG. 9 2 10 University of Tübingen, Sigwartstraße 10, 72074 Tübingen, 11 12 * corresponding author [email protected] 13 14 Keywords: , Isle of Wight, Chalk, lithostratigraphy, biostratigraphy, 15 16 17 Abstract 18 19 The Scratchell‟s Bay and southern Alum Bay sections, in the extreme west of the Isle 20 21 of Wight on promontory, cover the stratigraphically highest 22 formations available in southern . They are relatively inaccessible, other than 23 by boat, and despite being a virtually unbroken succession they have not received the 24 attention afforded to the Whitecliff GCR (Geological Conservation Review series) 25 site at the eastern extremity of the island. A detailed account of the lithostratigraphy 26 27 of the strata in Scratchell‟s Bay is presented and integrated with macro and micro 28 biostratigraphical results for each formation present. Comparisons are made with 29 earlier work to provide a comprehensive description of the Seaford Chalk, Newhaven 30 Chalk, Culver Chalk and Portsdown Chalk formations for the Needles promontory. 31 32 33 The strata described are correlated with those seen in the Culver Down Cliffs – 34 at the eastern end of the island that form the Whitecliff GCR site. This 35 provides an overall correlation for the Upper Coniacian to Upper Campanian Chalk 36 strata on the island. 37 38 39 The influence of the Purbeck – Wight structure ( and periclines) 40 on the Chalk Group strata is discussed and the conclusions drawn demonstrate that 41 movement on this structure is diachronous across the island. 42 43 44 45 1. Introduction 46 47 The Scratchell‟s Bay section on the western extremity of the Isle of Wight exposes a 48 49 virtually continuous section within the Seaford Chalk, Newhaven Chalk, Culver 50 Chalk, and Portsdown Chalk formations. South of the „Grand Arch‟ (Fig. 1 and 2) at 51 the eastern end of the bay the uppermost Nodular Chalk Formation is present 52 on and below a steeply shelving surface (the „grassed-surface‟ of Rowe (1908) and 53 Brydone (1914)). This part of the Chalk succession and the lowest part of the Seaford 54 55 Chalk Formation (the Belle Tout Beds of Mortimore, 1986) are only accessible at the 56 very lowest tides and were not logged nor sampled during the current BGS survey. 57 The highest part of the Portsdown Chalk Formation is present from the western end of 58 the bay, around the Needles promontory and along a strike section into Alum Bay to 59 the north (Fig. 1). This section is also only accessible at the very lowest tides and 60 61 62 63 64 65 consequently there is a small gap between the sections logged at Scratchell‟s Bay by 1 the survey team and with those logged by one of us (MAW) on the southern side of 2 Alum Bay beneath the Palaeogene . Data from other sources (Swiecicki, 3 4 1980; Gale, pers comm. 2008) demonstrates that the stratigraphical gap between the 5 BGS logs is small and represented by 30-35m of strata. It is also apparent that some 6 repetition or expansion of the succession within the Portsdown Chalk Formation and 7 possibly within the Seaford Chalk Formation within Scratchell‟s Bay and Alum Bay 8 may be present. This is as a consequence of strike orientated, bedding-parallel faulting 9 10 and/or due to a greater availability of accommodation space, resulting from movement 11 on the major Needles Fault structure, during deposition. The Culver Chalk Formation 12 is condensed relative to the Whitecliff GCR section. 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 Fig. 1. The location of the Scratchell‟s Bay and Alum Bay sections, Isle of Wight. 42 43 A full lithostratigraphical log of the Scratchell‟s Bay section is presented (Fig. 3a and 44 45 b). The strata were collected for macrofauna (relatively sparse for the succession 46 compared to elsewhere). A comprehensive series of microfaunal samples were 47 collected to aid correlation within section and more widely with the Whitecliff GCR 48 site. The microfaunal results provide an outline for the distribution of the 49 at this level within the Chalk Group (Fig. 4). A correlation with the succession within 50 51 the Whitecliff GCR site and other outline logs for Scratchell‟s Bay and Alum Bay is 52 presented (Fig. 5a and b). 53 54 1.1. Previous Research 55 56 57 Jukes Browne and Hill (1904) offer very little detail for „Scratchalls‟ Bay (their 58 spelling) other than repeating the statement of Whitaker (1865) and stating that the 59 “cliffs are only accessible by boat on a calm day” and describing the lowest part of the 60 61 62 63 64 65 coranguinum zone as “a bed of some thickness, in which the layers of 1 are so close together that they form nearly as much of the rock as the Chalk itself”. 2 This part of the Seaford Chalk succession was not accessible during the recent visit by 3 4 BGS but is clearly discernable in the photograph in Fig. 2a. A general view of the 5 Bay looking to the west is given in Fig. 2b. 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Fig, 2a. A view of Scratchell‟s Bay looking to the east. 37 The Grand Arch (centre above the distal end of the shingle beach) and Sun Corner (on the right 38 forming the „grass slope‟) are the two features most commonly referred to in articles on this section. 39 The regular flint seams characteristic of the Seaford Chalk Formation pass up-section to with 40 some flint and regular seams of the Newhaven Chalk Formation (extreme left of photograph). The 41 lowermost Seaford Chalk (the Belle Tout Beds of Mortimore, 1986) with their very closely-spaced flint 42 seams are indicated by the breaks of slope in the profile just above the grass slope. The higher 43 beds of the Lewes Nodular Chalk Formation form the slope and the cliffs below it. Figure in the mid 44 distance for scale is 2 m high. BGS Photo P 699954 P M Hopson ©NERC/BGS 45 46 47 The Geological Survey memoir (, 1921) likewise carries scant detail of this 48 important section relying instead on alluding to the descriptive accounts of Rowe 49 (1908) and Brydone (1914, 1918) and thereby giving estimates for biozonal 50 thicknesses for the units present. Both of these earlier authors present lithological 51 descriptions for the section, or part thereof, visible within the bay, although Rowe‟s 52 53 (1908) account does not provide a bed-by-bed account. Rowe gave the following 54 thicknesses for the zones he encountered M. cortestudinarium 15.24 m (of which 4.57 55 m appears in the cliff immediately above the „grass slope‟), M. coranguinum 95.5m, 56 U. socialis 10.52 m, M. testudinarius 14.33m, A. quadratus (in which Rowe included 57 58 the current U. anglicus and O. pilula zones) 104.55m, and B. mucronata for which he 59 gave no thickness. Only limited descriptions of the lithologies present in the section 60 are given in the memoir and only the section demonstrating Brydone‟s (1914) 61 62 63 64 65 lithological log for the stratigraphically higher part of the succession is printed. This 1 descriptive log is given as an outline graphic representation for comparison in Fig. 5(a 2 and b). Brydone (1914), in his on the Offaster pilula Zone, considered that the 3 4 Scratchell‟s Bay section offered the best section west of and regarded the 5 section at Culver Down – Whitecliff to be “notoriously abnormal”. Presumably 6 Brydone refers here to the obvious stratal condensation in what we now call the 7 Seaford Chalk Formation and the so-called „Flintless Belt‟ in the Newhaven Chalk 8 Formation, amongst other differences compared to the stratotype sections in Sussex. 9

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 Fig. 2b. Scratchell‟s Bay looking west towards the Needles from the observation 40 Photo P774681 P M Hopson ©NERC/BGS 41 platform above the Grand Arch. 42 43 Since these early descriptions of the section no further significant study was 44 undertaken until Swiecicki (1980). His unpublished PhD thesis included Scratchell‟s 45 Bay as one of 27 sections of Campanian and chalk from which he 46 47 developed foraminiferal biozonal schemes that he related to the macrofaunal 48 biozones. Three sections were logged in ; Scratchell‟s Bay and 49 Alum Bay on the Isle of Wight and Studland Bay to the west (only the 50 stratigraphically highest Campanian succession was studied here). The Scratchell‟s 51 Bay and Alum Bay exposures proved a near complete succession from the Upper 52 53 testudinarius biozone through to the Upper Campanian 54 Belemnitella mucronata macrofaunal biozone. A broad two-part planktonic 55 foraminiferal biozonation and a more comprehensive benthonic foraminiferal 56 biozonation (B1i-iii, B2i-iii and B3i-iii) were defined by Swiecicki (see Fig. 5 a and 57 58 b) for the Scratchell‟s Bay section. The eastern half of Scratchell‟s Bay, for the most 59 part exposing the Seaford Chalk Formation (middle-Coniacian to middle-Santonian) 60 61 62 63 64 65 was not included in that thesis. The relationship of these zones to those adopted by 1 BGS (British Geological Survey) are given in Wilkinson (this issue) 2 3 4 The complete scheme for the highest Chalk Group strata beyond that exposed on the 5 Isle of Wight equates with the benthonic foraminiferal biozones B1 to B7 of 6 Swiecicki (1980, Fig 2.1), and was developed utilising sections in East Anglia and 7 two wells in the . At Scratchell‟s Bay and Alum Bay the macrofaunal 8 correlation utilised in the Swiecicki PhD was derived from the work of Rowe (1908) 9 10 and Brydone (1914) together with additional macrofaunal material identified by C J 11 Wood (formerly of the BGS) for the author. 12 13 A log in manuscript form, for the eastern part of Scratchell‟s Bay, comprising the 14 15 Seaford Chalk Formation (coranguinum Zone), the Swiecicki section itself and a 16 section within Alum Bay are held by BGS as an addendum to the lithological log of 17 Swiecicki. It is unclear as to the origin of these logs but they carry macrofaunal 18 determinations by Chris Wood and regular microfaunal sample points and may well 19 be an early manuscript provided by Swiecicki to facilitate the interpretation of the 20 21 macro- determinations. 22 23 Mortimore (1986) established a lithostratigraphical correlation of the Chalk between 24 Whitecliff and the mainland successions of Portsdown and into Sussex, within the 25 expanded basinal successions of the Chalk Group. He utilised the Whitecliff section 26 27 as his holostratotype for the Culver Chalk Formation as this is more accessible than 28 that at the Scratchell‟s Bay. He did however recognise that the Scratchell‟s Bay 29 section was “more easily correlated with mainland sections” and broadly correlated 30 his Whitecliff section with it. 31 32 33 Bailey et al. (1983 and 1984) utilised, in part, the work of Swiecicki in establishing a 34 correlation of the biostratigraphical stages in southern England and presented the 35 biostratigraphical criteria on which the Coniacian-Maastrichtian stage boundaries in 36 the Chalk of north-west could be recognised in southern England. Bailey‟s 37 38 PhD thesis (Bailey, 1978) focussed on the more accessible Freshwater Bay and 39 Culver Cliff to define the foraminiferal zonation of the Coniacian and Lower 40 Santonian (Lower Senonian) on the Isle of Wight. He determined six assemblage 41 zones (A to F) that he applied to the Isle of Wight sections and these can be correlated 42 43 with the scheme of Hart et al. (1989) and BGS (see Wilkinson, this issue). The 44 scheme covers the Mid-Coniacian to Late Santonian (Seaford Chalk Formation and 45 lower Newhaven Chalk Formation) part of the succession encountered in Scratchell‟s 46 Bay. 47 48 49 Grant (1998) provides a sequence stratigraphy of the Culver Down / Whitecliff Chalk 50 succession that can be correlated with the Scratchell‟s Bay succession. Montgomery 51 (1994) and Montgomery et al. (1998) compare the magneto-stratigraphy of 52 Scratchell‟s Bay and Culver Down. 53 54 55 Hart et al. (1989) published a small-scale outline section for both Alum Bay (Upper 56 Campanian) and Scratchell‟s Bay (Santonian to late Campanian only) but this appears 57 to be a further presentation of the section utilised by Swiecicki (1980). This volume 58 carries the standard benthonic foraminiferal zones for the Chalk Group (UKB zones) 59 60 that is correlated with those of BGS in Wilkinson (this issue). 61 62 63 64 65

1 A complete manuscript lithological log from the Palaeogene unconformity in Alum 2 Bay around the Needles promontory and into Scratchell‟s Bay was kindly provided by 3 4 Professor Andy Gale (pers. comm., 2008). This matches closely with the section 5 logged by the BGS and is used in outline form (Fig. 5a and b) to aid correlation with 6 the Whitecliff GCR site (Mortimore et al., 2001). The Gale section (logged from 7 1992, presumably on a number of visits) permits correlation of the Alum Bay section 8 of Swiecicki (1980) and that of Woods (2009). It demonstrates that the Swiecicki 9 10 Alum Bay measured section is significantly too thick and perhaps emphasises the 11 difficulties of measuring stratal thicknesses in steeply dipping oblique sections. 12 13 14 15 2. The Scratchell’s Bay Section 16 17 The section examined during April/May 2008 by the BGS team is presented below in 18 Fig. 3a and 3b. These provide a graphical representation of the strata encountered and 19 their interpretation, based on the lithological changes noted together with the 20 21 correlation based on the micro- and macro-biostratigraphy. The log shows an 22 expanded Seaford Chalk Formation and a much reduced Culver Chalk Formation in 23 comparison to the Whitecliff GCR site. The of the Portsdown Chalk is not 24 clearly marked by the unequivocal presence of the Portsdown Marl pair. The 25 boundary is placed lower within the sequence compared to the interpretation of Gale 26 27 (see Fig 5a) based on the first occurrence of the foraminifera B. decoratus sensu 28 stricto, the indicator for the base of the Scratchell‟s and foraminiferal zone BGS 29 20iv, that is a little above the base of the Portsdown Chalk. 30 31 32 The section was sampled at frequent intervals for foraminifera. The ranges of the 33 principal indicative are given in Fig. 4 in relation to sample depth; their 34 interpretation in respect of the BGS foraminiferal scheme is indicated. These results 35 help fix the lithostratigraphical boundaries determined in Fig.3 a and b. 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 Fig. 3a. The Portsdown Chalk Formation, Culver Chalk Formation and upper part of 56 the Newhaven Chalk Formation exposed at Scratchell‟s Bay, Isle of Wight. (full page 57 58 place 3a and 3b on facing pages) 59 60 61 62 63 64 65 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 Fig. 3b. The lower part of the Newhaven Chalk Formation and the Seaford Chalk 57 Formation exposed at Scratchell‟s Bay, Isle of Wight. (full page place 3a and 3b on 58 59 facing pages) 60 61 62 63 64 65

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 Fig. 4. The distribution of key foraminifera identified in the Scratchell‟s Bay section 53 in relation to depth and the BGS zonal scheme. 54 55 3. Correlation 56 57 58 The Scratchell‟s Bay sections of Gale and BGS are the most readily matched and they 59 can be correlated with the successions at Whitecliff and with holostratotypes on the 60 mainland though with some important provisos discussed below. Difficulties with 61 62 63 64 65 matching the log of Brydone (1914), due to the lack of detail, and that of Swiecicki 1 (1980), because of marked thickness anomalies and emphasis on marker flint and 2 marl seams rather than chalk lithology, permit only an outline correlation with the 3 4 BGS and Gale logs shown in Fig. 5a and b. 5 6 3.1. Seaford Chalk Formation 7 8 The Scratchell‟s Bay logs demonstrate a significant increase in thickness of the 9 10 Seaford Chalk Formation (Fig. 5b and 6) by comparison to the Whitecliff GCR 11 section (Mortimore et al., 2001) and the holostratotype section at Seaford Head 12 (Mortimore, 1986). Whilst there is some potential repetition in part of the succession 13 at Scratchell‟s Bay, the overall thickness of the exposed and accessible part of the 14 15 formation is 89 metres. The stratigraphically older Belle Tout Beds representing the 16 lower part of the Seaford Chalk Formation below the Seven Sisters Flint, are un- 17 described at Scratchell‟s Bay as it falls within the cliff section offshore of the low- 18 water mark. The thickness of this unit is estimated at 15 m, based on an interpretation 19 of photographs; this represents a significant reduction compared to the Whitecliff 20 21 GCR section where the Belle Tout Beds are 25 m thick (Mortimore et al., 2001). 22 23 The greater part of the Cuckmere Beds forms the lower part of the BGS section 24 described from Scratchell‟s Bay, amounting to a minimum of 46 m of strata 25 above low-water. Neither the Gale nor the BGS logs identify the Seven Sisters Flint, 26 27 the basal marker for these beds. However, the presence of thick Platyceramus and 28 Volviceramus involutus, within the succession immediately above the low-water mark 29 suggest that this named bed can only be a short distance stratigraphically below the 30 logged section (indeed the Seven Sisters Flint may well be the large continuous flint 31 32 visible in Fig. 2). There is evidence of faulting within the BGS section and this may 33 have some potential to repeat the succession. However it is not clear how much of the 34 sequence is likely to be repeated, if any, as the fault, where seen on the foreshore, is 35 principally „within bed‟ and similar to those discussed in Mortimore et al. (2001, 36 p.187- 188) within the Shoreham and White Horse Marls at Whitecliff. Thus the 46 m 37 38 for the Cuckmere Beds may well be a true thickness. 39 40 At the top of the Cuckmere Beds the correlation of the Michel Dean Flint in both the 41 Gale and BGS logs at Scratchell‟s Bay is further justified by the occurrence of 42 43 Cladoceramus unduloplicatus at this level. This correlation indicates that the Haven 44 Brow Beds (cf Mortimore, 1986) are 43 m thick here, whilst a condensed 10 m are to 45 be seen at Whitecliff and 31 m at the Seaford Head holostratotype. The attenuation of 46 the upper Haven Brow Beds at Whitecliff culminates in two well-marked glauconitic 47 nodular beds and hardgrounds, the upper of which is a heavily glauconitized surface 48 49 overlain by coated intraclasts. This succession represents severe shoaling, 50 and probably wave-base remobilisation resulting from uplift on one element 51 of the developing Sandown fault/. This contrasts with the Scratchell‟s Bay 52 section, where all of the key Santonian marker can be recognised in an 53 expanded succession compared to the stratotype. This suggests that at Scratchell‟s 54 55 Bay greater accommodation space was available at this time and perhaps with an 56 influx of comprising winnowed material from further east. The 57 synchronicity of the expansion at Scratchell‟s Bay and the condensation at Whitecliff 58 precludes eustacy as a driving 59 60 61 62 63 64 65 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Fig. 5a. The principal features and correlation of the Portsdown Chalk and Culver 49 Chalk formations at Scratchells‟s Bay and their correlation to the Culver Down - 50 Whitecliff Bay GCR section. Outline logs derived from the work of Brydone (1914), 51 52 Swiecicki (1980), Gale (pers comm., 2008) and Mortimore et al., (2001). (print this 53 size place 5a and 5b on facing pages) 54 55 56 57 58 59 60 61 62 63 64 65

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 Fig. 5b The principal features and correlation of the Newhaven Chalk and Seaford 48 49 Chalk formations at Scratchells‟s Bay and their correlation to the Culver Down - 50 Whitecliff Bay GCR section. Outline logs derived from the work of Brydone (1914), 51 Swiecicki (1980), Gale (pers comm., 2008) and Mortimore et al., (2001). (print this 52 size place 5a and 5b on facing pages) 53 54 55 56 Mechanism. Rather, this is the clearest evidence from the two sections demonstrating 57 the influence of differential tectonism along the Purbeck – Wight Structure. 58 59 60 61 62 63 64 65 In conclusion, the Seaford Chalk Formation at Scratchell‟s Bay shows considerable 1 thickening in the uppermost Coniacian (Cuckmere Beds) and lower Santonian (Haven 2 Brow Beds) and some condensation in the mid-Coniacian (Belle Tout Beds). 3 4 5 3.2. Newhaven Chalk Formation 6 7 The Newhaven Chalk can correlated between Scratchell‟s Bay, Whitecliff and the 8 mainland stratotype, on the basis of lithological markers and the macro- 9 10 biostratigraphy and this is confirmed by the distribution of the foraminifera. The 11 succession is a little expanded at Scratchell‟s Bay compared to Whitecliff and 12 significantly more than at the stratotype in Sussex and much of this expansion is 13 within the Offaster pilula zonal interval. 14 15 16 17 Stratal Units Stratotype section Thickness at Thickness at Thickness at 18 name stratotype Whitecliff GCR Scratchell’s / 19 m Alum Bay 20 m m 21 Seaford Chalk Seaford Head 69 64 104 22 Formation 23 Belle Tout Beds Seaford Head 22 25 c.15 24 25 26 Cuckmere Beds Seaford Head 16 c.29 46+ 27 28 Haven Brow Beds Seaford Head 31 c.19 43 29 Newhaven Chalk Seaford Head 591 68 80 30 Formation 31 32 Culver Chalk Whitecliff 772 77 43 33 Formation 34 Tarrant Chalk Whitecliff 47 47 28 35 Member 36 37 Spetisbury Chalk Whitecliff 30 30 9 38 Member 39 Portsdown Farlington and 30+ 53 91 40 Chalk Formation Whitecliff* 63+* 41 42 Studland Chalk Alum Bay 22 43 Member 44 45 Fig. 6. Relative stratal thicknesses For Scratchell‟s Bay, Whitecliff and stratotypes for 46 the Chalk Formation in southern England 47 1 48 Excludes the Castle Hill Marls to Pepperbox Marls interval of about 5 metres thickness. 2 49 Whitecliff is the stratotype for this formation 50 51 3.3. Culver Chalk Formation 52 53 54 The Culver Chalk at Scratchell‟s Bay (c. 37 m) is greatly reduced in thickness 55 compared to that at Whitecliff (c. 77 m; the stratotype for this formation, Mortimore, 56 1986). In large exposures and under ideal geomorphological conditions during field 57 surveying, the Culver Chalk Formation is divisible locally into a lower Tarrant Chalk 58 Member and an upper Spetisbury Chalk Member. It has not proved possible to apply 59 60 this subdivision across the outcrop on the island, as the general steep dip does not give 61 62 63 64 65 rise to the characteristic geomorphological response (as minor scarps) for each of the 1 members as seen in Sussex. These members can be differentiated, however, in the 2 cliff sections at either end of the island and demonstrate the significant overall 3 4 reduction in thickness of both members at Scratchell‟s Bay compared to Whitecliff. 5 Further, the greater part of this reduction is accommodated within the younger 6 Spetisbury Chalk Member (the Whitecliff Beds of Mortimore, 1986) and the 7 uppermost Tarrant Chalk Member (upper Sompting Beds of Mortimore 1986) above 8 Marls. The mechanism for the reduction may be similar to the suggested 9 10 channelling within the Culver Chalk identified in the New Forest area at Bransgore 11 (Evans and Hopson, 2000; Evans et al. 2001) but may equally be simply a 12 condensation in response to local movement along the Brighstone pericline and 13 associated Needles Fault. 14 15 16 3.4. Portsdown Chalk Formation 17 18 The lower part of the Portsdown Chalk is described in the BGS log and can be 19 correlated closely to that by Gale. However the base of the formation is indicated 20 21 slightly lower in the succession by the presence of the indicator foraminifera B. 22 decoratus (base BGS 20iv zone, and placed at the Scratchell‟s Marls) in the sample at 23 47.25 m, and thereby further limits the thickness of the Culver Chalk below. This 24 inception places the formation boundary within a part of the succession without 25 significant marl seams, but with significant nodular flint horizons and two sheet flint 26 27 beds, and this suggests that the Portsdown Marls are weakly represented at 28 Scratchell‟s Bay. 29 30 The higher part of the Portsdown Formation is given in outline (Fig. 5a) derived from 31 32 the manuscript log of Gale and the short section description of Woods (2009) in Alum 33 Bay. The regularly spaced marl seams characteristic of the lower part of the formation 34 are identified in the succession as it is traced from Scratchell‟s Bay, around the 35 Needles, and into Alum Bay. The uppermost Portsdown Chalk in Alum Bay, 36 stratigraphically above the Alum Bay Marls of Gale (=Marl 1 of Swiecicki, 1980) is 37 38 assigned to the Studland Chalk Member (Gale et al., 1987; cf the Alum Bay Beds of 39 Mortimore, 1979, 1983). This member is essentially free of significant marl seams but 40 has regularly spaced large nodular flints. The stratigraphically highest significant marl 41 present at Whitecliff, associated with a group of Zoophycos flints, is a few metres 42 43 above the Flint (Mortimore et al., 2001). The correlation of this marl with 44 the Alum Bay Marls (of Gale) and the M1 Marl of Swiecicki (1980) would place the 45 stratigraphically higher Alum Bay Semitabular Flint (of Gale) within the group of 46 very large flints seams some 3-5 m below the Palaeogene unconformity at Whitecliff. 47 This correlation confirms that a substantial part of the chalk (c. 15 m) exposed in 48 49 Alum Bay is stratigraphically above that seen in the highest levels of the formation at 50 Whitecliff. 51 52 The presence of Echinocorys conica between 20.5 m and 23 m in the BGS log (Fig. 53 3a) indicates a position above the Farlington Marls of the Portsdown Chalk Formation 54 55 as indicated in Jenkyns et al. (1994 , Figure 15) at Whitecliff. Mortimore et al. (2001) 56 record a common occurrence of this species associated with their Culver Down Marls, 57 considerably higher in the Whitecliff succession. E. conica is also identified by C.J. 58 Wood on the manuscript of the Swiecicki log and is associated with the M9 marl on 59 60 that section (Fig. 5a). A tentative correlation is made between the BGS and Swiecicki 61 62 63 64 65 log on the basis of this fossil acme. The lowest occurrence of the foraminifera B. 1 decoratus is at 47.4 m (Fig. 3a). The inception of this species is at the base of the 2 Scratchell‟s Bay Marls, and its presence therefore indicates that the base of the 3 4 Portsdown Chalk Formation is only a short distance below the 47.4 m level. Since the 5 sample at 50.25 m is considered characteristic of BGS20iii zone and therefore highest 6 Culver Chalk Formation the formation boundary is located at approximately 48.5 m. 7 Thus the interval between 23 m and c. 48.5 m in the BGS logs should, at the very 8 least, contain the Portsdown Marl Pair, the full set of Scratchell‟s Marls (5) and the 9 10 three Bedhampton Marls. Only three marls are present within this 24.4 m interval, the 11 lower two of these being considered to be the Scratchell‟s Marls. This correlation 12 indicates that there is an expansion of the lowest part of the Portsdown Chalk 13 Formation at Scratchell‟s Bay compared to the 14 m present at Whitecliff. The 14 15 absence of marls is problematic in this part of the succession. They are either sheared- 16 out at Scratchell‟s Bay, they were never deposited or expansion has disseminated the 17 marl material over a greater thickness of chalk. 18 19 4. Discussion and Conclusions 20 21 22 The determination of the lithostratigraphical succession at Scratchell‟s Bay (BGS), its 23 correlation with other logged successions on the Needles promontory, and with the 24 Whitecliff GCR succession, demonstrates various differences that provide insights 25 into differential development and along the Purbeck-Wight Structure. 26 27 28 Some of the differences are significant and point to a syn-depositional (syn-rift) 29 tectonic control on the sedimentation and abrupt along-strike lithological changes as 30 discussed for example in Mortimore (2011) in the Chalk Group. 31 32 These tectonic controls are well illustrated and discussed in Mortimore (2011, and 33 references therein) and further justification for the existence of these controls is 34 provided here. Whilst time-constrained phases of basin-wide tectonic events have 35 been described across southern England (e.g. Mortimore and Pomerol, 1991a, b, 36 1997) and more widely across the Anglo into Germany (Mortimore et al., 37 38 1998) there is growing evidence that more localised events associated with individual 39 elements of larger fault and fold structures have profound effects on the detailed bed- 40 by-bed deposition of the Chalk (e.g. Gale, 1980) in addition to these basin-wide 41 events. The lithological contrasts determined between the Whitecliff and 42 43 Scratchell‟s/Alum Bay sites adds some additional data to that view, and point to 44 differential movement on the along-strike elements of the Purbeck – Wight Structure 45 as it is seen on the Isle of Wight itself, i.e. the Sandown and Brighstone (Needles) 46 folds and associated reverse faults. 47 48 49 Recent BGS geological mapping has identified a number of faults (with orientations 50 ranging from NW-SE through to NNE-SSW) that cross-cut the Purbeck – Wight 51 Structure. Other evidence of along strike changes in the Chalk (see Mortimore, 2011) 52 would suggest that these cross-cutting faults were active syn-depositionally and that 53 the developing regional fold/fault structures themselves did not act as single features 54 55 during tectonic movement but rather react sequentially to the stress field as it builds 56 up and is released within each along-strike element of the structure. 57 58 It is further envisaged, though not the main tenet of this paper, that these cross cutting 59 60 faults have been reactivated following the end of Chalk deposition, on at least two and 61 62 63 64 65 probably many more occasions. One such reactivation was pre-Palaeogene, 1 influencing the outcrop distribution of the highest chalk strata across the sub- 2 Palaeogene unconformity surface as indicated by the along-strike distribution of the 3 4 highest Chalk formations (e.g. as first discussed by Rowe, 1908, p. 285). The cross- 5 cutting relationship of the northerly-orientated faults and the Purbeck – Wight 6 Structure, demonstrated by recent mapping and seismic interpretation (Evans et al., 7 this issue), points to reactivation during the deposition of the Palaeogene. That this 8 reactivation took place on at least three occasions, is further justified by the evidence 9 10 of Palaeogene uplift and erosion afforded by Gale et al. (1999), during the Lutetian 11 and Bartonian, and by Newell and Evans (this issue), timed at the Bartonian - 12 Priabonian boundary. 13 14 15 In summary, variations in the thickness and lithology of the Upper Coniacian to 16 Upper Campanian Chalk succession show that:- 17  The thickness of the Portsdown Chalk Formation in Alum Bay interpreted by 18 Swiecicki is a significant overestimate compared to the thickness given in the 19 Gale log. 20 21  The base of the Portsdown Chalk is considered slightly lower stratigraphically 22 by BGS than that interpreted in the Gale section but that both sections show 23 an expansion of the lower Portsdown Chalk at Scratchell‟s Bay compared to 24 the Whitecliff GCR section. 25 26  There is considerable thinning of the Culver Chalk Formation in Scratchell‟s 27 Bay compared to the Whitecliff GCR site. 28  The expansion of the Newhaven Chalk Formation noted between the Sussex 29 type section and Whitecliff GCR site (Mortimore et al., 2001), continues with 30 31 the Newhaven Chalk Formation further expanded at Scratchell‟s Bay. 32  The condensation of the highest beds of the Seaford Chalk noted at Whitecliff 33 is not repeated at Scratchell‟s Bay where the thickest Seaford Chalk in 34 southern England is preserved. 35 36  Each of these thickness and lithological variations can be attributed to 37 differential movement along the Purbeck – Wight structure. 38 39 40 41 Acknowledgements 42 The authors would like to thank the National Trust for their permission to visit and 43 sample the Scratchell‟s Bay section. Thanks must go to the independently funded 44 Freshwater Lifeboat crews who so kindly helped transport the survey party to the bay 45 on two Sundays in April and May of 2008. Thanks also to Professor Andy Gale from 46 47 Portsmouth University for the sight of his manuscript notes and section drawn from 48 his visits to the exposure over a number of years and his permission to use this data to 49 support the outline log presented. 50 51 52 A manuscript section of the macrofossil determinations of Mr Chris Wood based on 53 the Swiecicki section log is lodged with the BGS at Keyworth and was consulted for 54 correlation purposes. This section includes data not presented in Swiecicki (1980) and 55 is added to the log in Fig. 5b. 56 57 58 The survey could not have been carried out without Katy Booth and Andy Newell of 59 the BGS and Rob Arnold, a visiting student from Cardiff University, who assisted 60 during the logging of the section. 61 62 63 64 65

1 Peter Hopson, Andrew Farrant, Ian Wilkinson, Sev Kender and Mark Woods publish 2 with the permission of the Executive Director British Geological Survey (NERC) 3 4 5 6 References 7 8 Bailey, H.W., 1978. A Foraminiferal Biostratigraphy of the Lower Senonian of 9 10 Southern England. Unpublished PhD thesis, Plymouth University. 11 12 Bailey, H.W., Gale, A.S., Mortimore, R.N., Swiecicki, A., Wood, C.J., 1983. The 13 Coniacian- Maastrichtian stages in the United Kingdom with particular reference to 14 15 southern England. Newsletters in Stratigraphy 12, 19-42. 16 17 Bailey, H.W., Gale, A.S., Mortimore, R.N. Swiecicki, A, Wood, C.J., 1984. 18 Biostratigraphical criteria for recognition of the Coniacian- Maastrichtian stage 19 boundaries in the Chalk of north-west Europe with particular reference to southern 20 21 England. Bulletin of the Geological Society of 33, 31-39. 22 23 Brydone, R.M., 1914. The Zone of Offaster Pilula in the south English Chalk. Part II 24 Isle of Wight. Geological Magazine 51, 405-411. 25 26 27 Brydone, R.M., 1918. The thickness of the zone of Belemnitella mucronata in the Isle 28 of Wight. Geological Magazine 55, 350-354. 29 30 Evans, D.J., Hopson, P.M., 2000. The seismic expression of synsedimentary channel 31 32 features within the Chalk of southern England. Proceedings of the Geologists‟ 33 Association 111, 219-230. 34 35 Evans, D.J., Hopson, P.M., Kirby, G.A., Bristow, C.R., 2003. The development and 36 seismic expression of synsedimentary features in the Chalk of southern England. 37 38 Journal of the Geological Society of London 160, 797-814. 39 40 Evans, D.J., Kirby, G.A., Hulbert, A.G., 2011. New insights into the structure and 41 evolution of the Isle of Wight . Proceedings of the Geologists‟ Association 42 43 122, XXX-XXX page numbers to be added 44 45 Gale, A.S., 1980. Penecontemporaneous folding, sedimentation and erosion in 46 Campanian Chalk near Portsmouth, England. Sedimentology 27, 137-151. 47 48 49 Gale, A.S., 2008. Pers Comm. Manuscript notes and section details for Scratchell‟s 50 Bay and Alum Bay. 51 52 Gale, A.S., Jeffrey, P.A., Huggett, J.M., Connolly, P., 1999. inversion history 53 of the Sandown Pericline, Isle of Wight, southern England. Journal of the Geological 54 55 Society of London 156, 327-339. 56 57 Gale, A.S., Wood, C.J., Bromley, R.G., 1987. The lithostratigraphy and marker bed 58 correlation of the White Chalk (late - Campanian) in southern England. 59 60 Research 1, 107-118. 61 62 63 64 65

1 Grant, S.F., 1998. Sequence stratigraphy of a pelagic chalk succession: The Coniacian 2 – Lower Campanian of the Anglo-Paris Basin. Unpublished PhD thesis, University of 3 4 Durham. 5 6 Hart, M.B., Bailey, H.W., Crittenden, S., Fletcher, B.N., Price, R.J., Swiecicki, A., 7 1989. 273-371 Chapter 7, Cretaceous. In, Jenkins, D.G., Murray, J.W., Eds, 8 Stratigraphical Atlas of Fossil Foraminifera, 2nd Edition. Ellis Horwood Ltd, 9 10 Chichester. 11 12 Jenkyns, H.C., Gale, A.S., Corfield, R.M., 1994. Carbon- and oxygen-isotope 13 stratigraphy of the English Chalk ansd Italian Scaglia and its palaeoclimatic 14 15 significance. Geological Magazine 131, 1-34. 16 17 Jukes-Browne, A.J., Hill, W., 1904. The Cretaceous Rocks of Britain, Volume 3 the 18 Upper Chalk of England. Chapter VII, Isle of Wight. Memoir of the Geological 19 Survey of the United Kingdom. 20 21 22 Montgomery, P., 1994. The Magnetostratigraphy of Coniacian – Late Campanian 23 Chalk sequences of southern England. Unpublished PhD thesis, University of 24 Southampton. 25 26 27 Montgomery, P., Hailwood, E.A., Gale, A.S., Burnett, J.A., 1998. The 28 magnetostratigraphy of the Coniacian – Late Campanian Chalk sequences in southern 29 England. Earth and Planetary Science Letters 156, 209-224. 30 31 32 Mortimore, R.N., 1979. The relationship of stratigraphy and tectonofacies to the 33 physical properties of the White Chalk of Sussex. Unpublished PhD thesis, University 34 of Brighton. 35 36 Mortimore, R.N., 1983. The stratigraphy and sedimentation of the – 37 38 Campanian in the southern province of England. Zitteliana 10, 27-41. 39 40 Mortimore R.N., 1986. Stratigraphy of the Upper Cretaceous White Chalk of Sussex. 41 Proceedings of the Geologists‟ Association 97, 97-139. 42 43 44 Mortimore, R.N., 2011. Structural geology of the Upper Cretaceous Chalk Central 45 Mass, Isle of Wight, UK. Proceedings of the Geologists‟ Association 122, 298-331. 46 47 Mortimore, R.N., Pomerol, B., 1991a. Upper Cretaceous tectonic disruptions in a 48 49 placid Chalk sequence in the Anglo-Paris Basin. Journal of the Geological Society of 50 London 148, 391-404. 51 52 Mortimore, R.N., Pomerol, B., 1991b. Stratigraphy and eustatic implications of trace 53 fossil events in the Upper Cretaceous Chalk of Northern Europe. Palaios 6, 216-231. 54 55 56 Mortimore, R.N., Pomerol, B., 1997. Upper Cretaceous tectonic phases and end 57 Cretaceous inversion in the Chalk of the Anglo-Paris Basin. Proceedings of the 58 Geologists‟ Association 108, 231-255. 59 60 61 62 63 64 65 Mortimore, R.N., Wood, C.J., Gallois, R.W., 2001. British Upper Cretaceous 1 Stratigraphy. Geological Conservation Review Series, No. 23, Joint Nature 2 Conservation Committee, Peterborough. 3 4 5 Mortimore, R.N., Wood, C.J., Pomerol, B., Ernst, G., 1998. Dating the phases of the 6 Subhercynian tectonic epoch: Late Cretaceous tectonics and eustatics in the 7 Cretaceous basins of northern Germany compared with the Anglo-Paris Basin. 8 Zentralblatt für Geologie und Paläeontologie, Teil 1, 1996,(11/12), 1349-1401. 9 10 11 Newell, A.J., Evans, D.J., 2011. Timing of basin inversion on the Isle of Wight: New 12 evidence from geophysical log correlation, seismic sections and lateral facies change 13 in the Headon Hill Formation. Proceedings of the Geologists‟ Association 122, XXX- 14 15 XXX. page numbers to be added 16 17 Rowe, A.W., 1908. The zones of the White Chalk of the English Coast. Part 5, The 18 Isle of Wight. Proceedings of the Geologists‟ Association 18, 209-352. 19 20 21 Swiecicki, A., 1980. A foraminiferal biostratigraphy of the Campanian and 22 Maastrichtian Chalks of the United Kingdom. Unpublished PhD Thesis, Plymouth 23 Polytechnic. 24 25 Whitaker, W., 1865. On the Chalk of the Isle of Wight. Quarterly Journal of the 26 27 Geological Society of London 21, 400-406. 28 29 White, H.J.O., 1921. A short account of the geology of the Isle of Wight. Memoir of 30 the British Geological Survey. 31 32 33 Wilkinson, I.P., 2011. Foraminiferal biozones and their relationship to the 34 lithostratigraphy of the Chalk Group of southern England. Proceedings of the 35 Geologists‟Association 122, XXX-XXX. page numbers to be added 36 37 38 Woods, M.A., 2009. Macrofossils from the Upper Formation and Chalk 39 Group of the Isle of Wight: Spring 2009. British Geological Survey Internal Report 40 IR/09/056. 41 42 43 Figure Captions 44 45 Fig. 1. The location of the Scratchell‟s Bay and Alum Bay sections, Isle of Wight. 46 47 Fig, 2a. A view of Scratchell‟s Bay looking to the east. 48 The Grand Arch (centre above the distal end of the shingle beach) and Sun Corner (on the right 49 forming the „grass slope‟) are the two features most commonly referred to in articles on this section. 50 The regular flint seams characteristic of the Seaford Chalk Formation pass up-section to chalks with 51 some flint and regular marl seams of the Newhaven Chalk Formation (extreme left of photograph). The 52 lowermost Seaford Chalk (the Belle Tout Beds of Mortimore, 1986) with their very closely-spaced flint 53 seams are indicated by the breaks of slope in the cliff profile just above the grass slope. The higher 54 55 beds of the Lewes Nodular Chalk Formation form the slope and the cliffs below it. Figure in the mid 56 distance for scale is 2 m high. BGS Photo P 699954 P M Hopson ©NERC/BGS 57 58 Fig. 2b. Scratchell‟s Bay looking west towards the Needles from the observation 59 platform above the Grand Arch. Photo P774681 P M Hopson ©NERC/BGS 60 61 62 63 64 65

1 Fig. 3a. The Portsdown Chalk Formation, Culver Chalk Formation and upper part of 2 the Newhaven Chalk Formation exposed at Scratchell‟s Bay, Isle of Wight. (place 3a 3 4 and 3b on facing pages) 5 6 Fig. 3b. The lower part of the Newhaven Chalk Formation and the Seaford Chalk 7 Formation exposed at Scratchell‟s Bay, Isle of Wight. (place 3a and 3b on facing 8 pages) 9 10 11 Fig. 4. The distribution of key foraminifera identified in the Scratchell‟s Bay section 12 in relation to depth and the BGS zonal scheme. 13 14 15 Fig. 5a. The principal features and correlation of the Portsdown Chalk and Culver 16 Chalk formations at Scratchells‟s Bay and their correlation to the Culver Down - 17 Whitecliff Bay GCR section. Outline logs derived from the work of Brydone (1914), 18 Swiecicki (1980), Gale (pers comm., 2008) and Mortimore et al., (2001). (print this 19 size place 5a and 5b on facing pages) 20 21 22 Fig. 5b The principal features and correlation of the Newhaven Chalk and Seaford 23 Chalk formations at Scratchells‟s Bay and their correlation to the Culver Down - 24 Whitecliff Bay GCR section. Outline logs derived from the work of Brydone (1914), 25 Swiecicki (1980), Gale (pers comm., 2008) and Mortimore et al., (2001). (print this 26 27 size place 5a and 5b on facing pages) 28 29 Fig. 6. Relative stratal thicknesses For Scratchell‟s Bay, Whitecliff and stratotypes for 30 the Chalk Formation in southern England 31 1 Excludes the Castle Hill Marls to Pepperbox Marls interval of about 5 metres thickness. 32 2 Whitecliff is the stratotype for this formation 33

34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Figure

Cowes 55 Alum Bay Yarmouth Alum Newport Bay Culverdown/ Scratchell’s Whitecliff Bay Bay

0 10 km

West High Down 50

The Needles Battery

Lighthouse The Needles Coastguard station Scratchell’s Bay Grand Arch

St Anthony Rock Preston’s Sun Corner Bower 0 500 m 08 45

42 90 95 43 00 05

Palaeogene Newhaven Chalk New Pit Chalk Roads Formation Formation

Portsdown Chalk Seaford Chalk Major cliff failure Formation Formation Cliffs Culver Chalk Lewes Nodular Formation Chalk Formation Figure Click here to download high resolution image Figure Click here to download high resolution image Figure Click here to download high resolution image Figure Biostratigraphy Lithostratigraphy zone BGS Foram Depth Biostratigraphy Lithostratigraphy zone BGS Foram Depth Biostratigraphy Lithostratigraphy zone BGS Foram Depth Biostratigraphy Lithostratigraphy zone BGS Foram Depth Biostratigraphy Lithostratigraphy zone BGS Foram Depth 0m 30 60 90 120

m m BGS 19

m m m m m

sp 5 35 65 95 125 sp

sp sp m sp m sp sp pilula Offaster

sp sp sp sp sp sp m sp BGS 21i sp sp m sp sp sp Belemnitella mucronata

m BGS 20iv m

10 40 70 100 130 PORTSDOWN CHALK FORMATION PORTSDOWN

m m m BGS 20i-ii sp sp sp sp sp m Gonioteuthis quadrata sp sp sp

CULVER CHALK FORMATION CHALK CULVER sp sp sp sp sp sp sp sp sp m 15 45 75 105 135 m m m Scratchell’s sp sp sp sp

Marls BGS 19 sp sp sp sp Offaster pilula Offaster Gonioteuthis quadrata FAULT sp sp sp sp PORTSDOWN CHALK FORMATION PORTSDOWN NEWHAVEN CHALK FORMATION NEWHAVEN m m CHALK FORMATION NEWHAVEN spsp sp BGS 18iii-iv m ?Level of Portsdown Marls m

20 50 80 110 140 m m sp sp sp m

m m Marsupites testudinarius E.conica sp sp sp

BGS 20iv m

Brighton Marl BGS 20iii sp sp sp Gonioteuthis quadrata m

sp sp sp m 25 55 m 85 115 145

m

sp sp sp sp CULVER CHALK FORMATION CHALK CULVER

m ? PY ?Farlington Marl m BGS 19 Offaster pilula Offaster BGS 20i-ii m m

NEWHAVEN CHALK FORMATION NEWHAVEN sp sp sp sp 30 60 90 120 soc U. 150 Figure Click here to download high resolution image Figure Click here to download high resolution image Figure Biostratigraphy Lithostratigraphy zone BGS Foram Depth Biostratigraphy Lithostratigraphy zone BGS Foram Depth Biostratigraphy Lithostratigraphy zone BGS Foram Depth Biostratigraphy Lithostratigraphy zone BGS Foram Depth 150 180 210 240

BGS 18iii-iv m BGS 17iii BGS 17i-ii 155 185 215 245

m ? m

m BGS 18ii Uintacrinus socialis sp sp sp sp Micraster coranguinum

Biostratigraphy Lithostratigraphy zone BGS Foram Depth sp sp sp sp NEWHAVEN CHALK FORMATION NEWHAVEN m 159 SEAFORD CHALK FORMATION

160 160 190 220 250

sp sp sp sp sp sp sp

sp sp sp BGS 16

m Uintacrinus socialis NEWHAVEN CHALK FORMATION NEWHAVEN BGS 18i

165 165 195 225 255 m

End of available section BGS 17i-ii Micraster coranguinum Micraster coranguinum Nodular-tabular SEAFORD CHALK FORMATION SEAFORD CHALK FORMATION flint seams Sheet flint m Marl seam

sp sp sp sp

BGS 17i-ii Common traces 170 170 200 230 ‘Gritty’ chalks m

BGS 17iii Heavily bioturbated chalks

Marsupites testudinarius m Sample point for micro

Inoceramid debris BGS 17iii SEAFORD CHALK FORMATION

(mi)

m Fe Fe

175 Micraster coranguinum 175 205 235 SEAFORD CHALK FORMATION

f

177

m

180 210 240 Figure Click here to download high resolution image Figure

SWIECICKI ALUM BAY 1980

70 BGS INTERPRETATION OF MANUSCRIPT ALUM BAY AS GALE SCRATCHELL’S BAY 2008 & ALUM BAY SECTION

60 Studland Chalk Member 10 Top of chalk 140

50 0 CULVER DOWN/WHITECLIFF 130 GCR SECTION Alum Bay MORTIMORE et al. (2001) 40 semi tabular

120 ? PORTSDOWN CHALK FORMATION 30 ? 140 Belemnitella mucronata M1 110 Approximate level 110 SWIECICKI M2 of Needles Flint SECTION 20 Zoophycos flints 1980 This section greatly expanded in original log 130 100 100 M3 100 Yarbridge Flint Zoophycos flints 10 M4 M7 Culver Down Marls M5 120 UNLOGGED INTERVAL Marl 2 90 90 90 Brading Marl 1 gritty chalks 0 110 M8 ?Shide Marl BRYDONE 80 80 SECTION 80 Down Marl 1914 M9 E.conica gritty chalks Arreton Down 100 Triple Marl Shide Marl CAMPANIAN 70 70 70 M10/11 Farlington Marls E.conica chalk with 2 marls M12/13 Farlington Marls B.muc ? marl M14 90 Bedhampton Marl 2/3 G.quad Bedhampton Marl 1 B3i M15 60 ?Scratchells Marls 60 60 Scratchell’s Marl 4/5 M16- Scratchell’s Flint paramudra Scratchell’s Marl 3 M17 Portsdown Marls Scratchell’s pair 80 of marls gritty chalks PCk Portsdown Marls PCk 50 50 Portsdown pair 50 of marls

marl Spetisbury Chalk Member tabular flint Cotes Bottom Flint marl ? 70 Warren Farm PCk Level of Portsdown chalk with a 40 Paramudra tabular flint 40 40 Marls M19 Top of marl Zoophycos flints 60 Whitecliff flint M20 Marl 3 CULVER CHALK FORMATION B2iii Gonioteuthis quadrata 30 heavily bioturbated 30 Yaverland Marl 2 30 chalks ?Solent Marls Yaverland Marl 1

marl Charmadean Flint chalk with three marls 50 marl ?Solent Marls Double flint 20 20 Whitecliff marl 20 Lancing Marl 2 Wispy Marls paramudra flints M22 Tarant Chalk Member B2ii Lancing Marl 1 Cotes Bottom Flint M23 40 double flint marl 10 10 10 chalk with six marls Laminated chalks M24 CCk M25/26 30 CCk marls base G.quad NCk CCk NCk B2i M28 Solent Marl 3 0 0 Pepperbox Marls B1iii0 NCk Solent Marl 2 O.pilula Castle Hill Marls Solent Marl 1 planoconvexus Charmandean 20 Flint Lancing Marl 2 paramudra flints Lancing Marl 1 10 paramudra Lancing Flint paramudra CCk FORMATION 0 NEWHAVEN Major marls Pepperbox Marls

NCk CHALK Major flints Castle Hill Marls Figure

INTERPRETATION OF MANUSCRIPT AS GALE SCRATCHELL’S BAY FORMATION & ALUM BAY SECTION Offaster pilula Gonioteuthis quadrata CULVER CHALK CCk Pepperbox Marls SWIECICKI Castle Hill SECTION BGS STRATCHELL’S Marls BRYDONE 2008 SECTION BAY SECTION Black Rabbit Marl 170 CULVER DOWN/WHITECLIFF 1914 2008 Telscombe Marls B2i M27 CCk O.pil GCR SECTION CCk M28 G.quad Castle Hill Marls Pepperbox Marls MORTIMORE et al. (2001) 80 O.pil Upper belt of

O.pilula 160 CAMPANIAN marl 160 CCk Pepperbox Marls 70 140

150 Castle Hill Marls NEWHAVEN CHALK FORMATION chalk with 6 marls 150 Portobello Lower belt of Zoophycos 60 B1iii O.pilula Old Nore Marl O.pilula O.pil 130 beds Old Nore Marl 140 (Brydone’s Strong Marl) 140 Telscombe Marl Meeching Marls 50 chalk with 8 marls 120 Old Nore Marl and 2 flint tabulars 130 B1ii 130 strong marl B1i Level of Friars Bay Marl 3 strong marl Base Swiecicki U.anglicus Uintacrinus 40 anglicus strong tabular flint PhD log 110 strong marl 120 Level of Friars Bay very strong marl Log derived from Marl 1 testudinarius =Brighton Marl C.Wood. Manuscript 120 M.test Marsupites log after Swiecicki 30 100 Brighton Marl? M.test 110 v. strong marl 110 Brighton Marl M.test Top U. soc zone 20 90 stylolitic large flints Level of Hawks Brow Flint marls 100 strong flint Uintacrinus 100 socialis strong marl U.soc U.soc 10 abundant 80 SANTONIAN marl 90 marl NCk NCk U.soc 90 NCk NCk U. soc ? Buckle Marl Buckle Marl strong flint Buckle Marl glauconite 0 Exceat Flint 70 glauconite Exceat Flint Brass Point Flint 80 80

Gap 60 ?Flat Hill Flint 70 Short Brow Flint Cladoceramus Short Brow Flint? 70 Rough Brow Flint Michel Dean Flint

Rough Brow Flint SEAFORD CHALK FORMATION (Whitakes 3”) (Whitakes 3”) Micraster coranguinum 50 Tarring Neville Flint Rough Brow Flint? Sponges 60 60 Brass Point Flint White Horse Marl 1 Brass Point Flint? 40 Thick Platyceramus Cladoceramus 50 Flat Hill Flint 50 Cladoceramus Michel Dean Flint 30 ?Michel Dean Flint Volviceramus Michel Dean Flint? 40 40 Seven Sisters Flint Volviceramus 20 F Significant repeat of beds in this part? 30 Belle Tout Marl 3 30 Belle Tout Marl 2 Belle Tout Marl 1 CONIACIAN 10 20 20 SCk 0 Shoreham Marls LeCk marl 10 10 Thick Platyceramus LEWES NODULAR M.cortestudinarium FORMATION Volviceramus 0 CHALK SCk Major marls 0 SCk Major flints Figure Click here to download high resolution image Figure Click here to download high resolution image