58 



HARDWICKE'S SCIENCE-GOSSJP. 



chief Lower Headon limestone (How Ledge lime- 

 stone) Appean bands of limestone separated by beds 

 of clay occur just like those of Totland Bay. The 

 lowest of these clays passes down into the Upper 

 Eagshot sand, where the section was picked up on 

 the following day. Many good opportunities for 

 collecting occurred at various spots round the hill ; 

 for instance, beautiful specimens of Paludina lenta 

 occur in one place weathered out from the clay above 

 the Upper Headon limestone ; then, often good speci- 

 mens of Planorbis and Limmea occur weathered out, 

 while the common fossils of the Middle Headon, 

 such as Cyrena obovata, Cerithiuvi vcntricosiim, and 

 C. concaviim, occur in thousands, and many other of 

 the fossils are easily found. The section at the south 

 end of Headon Hill very closely resembles that of 

 Totland and Colwell Bays, with the few exceptions 

 mentioned above, and except in the case of one or 

 two local thickenings such as the Upper Headon 

 limestone and the Osborne limestone, which are 

 thicker than elsewhere. 



On the following day I went straight to Alum Bay, 

 and picking up the section at the Upper Bagshot 

 sands, where I left it on the previous day, I continued 

 to work my way downwards. The upper sands 

 showed little of interest, except some beautifully 

 white sand, with a high dip indicating a very sharp 

 bend in strata which are almost horizontal in Headon 

 Hill. 



The Barton beds were searched with considerable 

 profit, and yielded specimens of Fusus lo7iga:vns, 

 Vohita sphiosa, Chama squamosa, Corbula pisu}?i, 

 nummulites, &c. The shells were best collected 

 weathered out in the cliffs and taluses. 



The Bracklesham beds below the Barton are 

 unfossiliferous in Alum Bay, but still they are inter- 

 esting in several respects, for they contain beds of 

 lignite which show underclays with rootlets. At 

 their top too, or rather perhaps at the bottom of the 

 Braton beds, occurs a band of rounded flint pebbles, 

 which stands out from the more easily weathered 

 sands, and looks threateningly down on those who 

 pass below. Some of the sands are of an unusual 

 colour, one band being a beautiful crimson. 



The next group is the thick sands of the Lower 

 Bagshot, which furnish most of the well-known Alum 

 Bay sands. The most interesting band of this is one 

 of the beds of pipe-clay, from which a large number 

 of leaves have been collected. 



The London Clay is not a very interesting deposit, 

 as it consists of a monotonous dark clay with occa- 

 sional bands of septaria or clay ironstone, or a band 

 of pebbles and few fossils. Panopaa iiitermedia and 

 Pholadomya margariticea may, however, be collected, 

 with some gasteropoda and occasionally a septarian 

 nodule crowded with shells. 



The curious mottled Plastic Clay is the lowest bed 

 of the Tertiaries, and is probably equal to the 

 Woolwich and Reading beds of the London basin. 



This clay rests on a fairly regular base of chalk with 

 flints, and is at a very high angle of dip, and towards 

 the top of the section, inverted. 



The chalk contains few fossils. A curious point 

 about it is that the flints generally smash to pieces on 

 being touched with a hammer, due to a brecciation 

 in situ, probably induced by the same forces which 

 produced the rolls in the strata, as Mr. Bristow 

 suggests. 



The next two days, though an inadequate time, 

 were all I could afford to spend on the Secondary 

 geology of the island, and that only on the western 

 side. 



The first of these days was spent at Compton Bay, 

 where I started geologising underneath the great 

 chalk cliff". A few Upper Greensand and Chalk Marl 

 fossils were found, Ostrea vesiculosa and annelida, 

 and a large ammonite. The Gault was not well 

 exposed, as the slips from it encourage vegetation ; 

 it contains few fossils. Neither is the Lower Green- 

 sand very fertile in fossils here, and it seems thinner 

 than on the south side of the Atherfield anticlinal. 

 The Wealden strata, however, were well exposed 

 and fossils obtained from several beds, some of which 

 were exposed on the strand and others in the cliffs. 

 The beds seemed to be of a great thickness, but the 

 low dip doubtless made the thickness appear greater 

 than it really was. Besides finding Cypris, Paludina 

 and Cyrena in the soft and hard clays, masses of 

 wood were weathered out on the shore. The Wealden 

 strata come to an anticlinal at Brook Point, and as 

 the axis of the bend is inclined, lower and lower beds 

 are found out at sea when the tide is low. I was 

 not lucky enough to see the pine raft, or fossil forest, 

 which is exposed here when the tides are very low. 



The section from Brook Point to Atherfield Point 

 is not very interesting and not particularly well 

 exposed, so the following day I started at Atherfield, 

 where the lowest beds of the Lower Greensand come 

 in, in their fullest development, in a series of magni- 

 ficent cliffs. It is not necessary to give a detailed 

 account of the beds, as they are ss well given in 

 Bristow's "Memoir." I was not able to spend very 

 long in collecting, as I had to make my way to 

 Ventnor, and thence to Sandown that night. I had 

 time, however, to collect fossils from the Lower 

 Exogyra group, amongst which were Terebratiila 

 sella, Rhynchonella Gibbsii, Exogyra colitmba, and a 

 Pecten, and also a Serpula and Rhynchonella from 

 the Walpen clay and sand. 



I made my escape from the shore by means of a 

 ladder and other conveniences for climbing which 

 now disfigure the beautiful Blackgang Chine, and 

 walked along the magnificent mural cliff to Ventnor, 

 whence I took train to Sandown. 



The last day was spent in an exploration of the 

 Tertiaries of Whitecliff Bay, where a walk from San- 

 down over Bembridge Down soon brought me. The 

 view from this down, to my mind, is unsurpassed in 



