TKANSACTIOHS OF SECTION C. 521 



Vertical Section at the North-east Corner of Hendon Hill. — One hundred and 

 ten feet of strata occur from the top of the Bemhridge limestone to the top of the 

 Great Limestone (Upper Headon). The Brockenhurst series does not exist 

 here. Not a single marine fossil occurs in that interval. Nor is there any bed 

 having the least resemblance either lithologically or palaeontologically to the 

 Colwell Bay Venus bed. 



The Upper Headon at Headon Hill measures 50 feet, and contains the thick 

 Lymnsean limestone (27 feet). The united or combined thickness of the Osborne 

 and Upper Headon beds (Geological Survey) is 119 feet, i.e. adopting the top of 

 the Cerithimn ventricosum bed as the boundary. The Osborne beds at Headon 

 HiU are below the Bembridge limestone and extend up to it, so there is no room 

 for a greater thickness of beds. 



The Middle Headon. — The uppermost and lower portions of the Middle Headon 

 are brackish-water beds abounding in Cerlthinm ventricosum, C. pseudocinctum, 

 C. concavum, Neritina concava, and NemnturcB. The beds or series in Headon Hill 

 richest in Cytherea incrassata (Venus bed proper), exhibit identically the same 

 fossils as at Colwell Bay. 



Below the oyster band in grey sandy clays is the Venus bed, extremely rich in 

 marine fossils. Cytherea, Mya, Maetra, Corbicida, Nucula, Triyonocoelia, Fusus, 

 Cancellaria, Voluf.a, Vicarya, and Natica ; Mya umjtistata and Cytherea incrassata 

 scattered throughout and abiuidant. The Middle Headon of Headon Hill is 32 feet 

 thick. The Survey vertical section gives 35 feet for the same boundaries. The 

 height of the Middle Headon above the sea-level at the north-east end is 72 feet, 

 and not below the sea-level, as seems required on Professor Judd's theory. 



Lower Headon. — The first bed is a Lymnsean limestone, and is the same well- 

 known bed which forms the top of the Lower Headon in Warden Olilf. It is 

 traceable to How Ledge, where it disappears below the sea, and clearly shows by its 

 course that it is the How Ledge bed of Warden Cliff. Although this limestone is 

 denuded from the top of the anticlinal curve between W^eston and Widdick Chines, 

 some of the lower beds are traceable the whole distance ; accordingly we can join 

 on the section in Headon Cliff to that in Warden Cliff. This gives a continuous 

 section and series of beds from the lowest seen of the Lower Headon, through the 

 Middle and Upper Headon of Colwell Bay to the Bembridge limestone both north 

 and south. There is therefore only one marine {Middle Headon) series lying 

 between two freshwater series, or ' the Lower and Upper Headon.' The E-ev. 

 0. Fisher has discovered the Venus bed in the Totland Bay brickyard, some short 

 distance above and behind the top of the cliff, between the chines. This being the 

 only part where it is missing from the cliff is proof of its continuity from Warden 

 Cliff to the north-east corner of Headon Hill. 



The authors describe in the most careful manner the Lower Headon beds of the 

 cliffs between Weston and Widdick Chines, much of the space in which is hidden 

 by the grass slopes, but the connection cannot be doubted. 



The Lower Hendon of Warden Cliff.- — ' The lowest beds of this series are seen 

 below the Totland Bay Hotel at Weston Chine, and all are below the Venus bed. 

 A remarkable feature in the lowest portion are five thin Lymnsean limestones, con- 

 taining chara seeds. These five limestones at low water form ^\e submarme ledges 

 parallel to the great ledge at Warden cliff' (Warden ledge). Above these five beds 

 and the sands containing Potamomya comes the concretionary calcareous sand rock 

 which forms AVarden Ledge. It crops out at the top of the cliff below the flagstafi" 

 of the coastguard station. Succeeding these is the tJnio bed (^U. Sohmdri) which is 

 associated with Melania turritissimn. The How Ledge limestone succeeds and forms 

 the summit of the Lower Headon series. This limestone is denuded away in the 

 centre of Totland Bay, where we have evidence and may infer the summit of the 

 anticlinal to be near the old wooden pier. The thickness of the Lower Headon in 

 Warden cliff is 72 feet, and from that to 87 feet before reaching the yellow sands 

 of the Upper Bagshot. 



The whole of tlie cliffs between Weston and Widdick Chines are occupied solely 

 and throughout by Lower Headon beds, and the Colwell Bay marine bed extends 

 all through Warden point and clifi", where it rests upon, or is supported by, the How 



