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HARDWICKE'S SCIENCE-GOSSIP. 



\ WEEK'S RAMBLING WITH A HAMMER 

 IN THE ISLE OF WIGHT. 



By W. W. Watts, E.A. 



AN account of a week's geologising in the Isle of 

 Wight may be not uninteresting to some of 

 the readers of Science Gossip, not as offering any 

 new or original matter, but rather to induce more 

 students to make use of this delightful epitome of 

 Cretaceous and Eocene geology. I do not propose to 

 give minute details of the strata, for they will be 

 found at full length in the memoirs on the subject— 

 for instance, the "Geological Survey Memoirs," by 

 Bristow and Forbes, and the recent paper by Messrs. 

 Tawney and Keeping (QJ.G.S. May, 1881, p. 85)— 

 but merely to indicate the general plan of work 

 pursued, and to give a few details of the principal 

 strata met with. 



The first day was taken up by a visit to the Ham- 

 stead cliffs, where the strata from the Hamstead 

 Corbula beds to the I'.embridge limestone are well 

 exposed. It is a wild and lonely place, overgrown 

 by furze and wood, even down to the water's edge 

 at high tide, and then quite impassable near the sea. 

 The cliffs are in a terrible state of tumble-down, and 

 great care is requisite in going about them if the 

 weather is not dry, for the soft marls and clays are 

 washed into a viscous mud by the rain, and this 

 mud flows down in a kind of glacier, bearing to 

 the sea-level a load of debris fallen from the cliffs, 

 from which fine specimens of the characteristic fossils 

 may be collected ; many of the fossils are thus borne 

 down and mingled with the deposits now forming 

 along the shore line, and are not necessarily more 

 rolled in the deposit than the recent shells there. 



A detailed section is unnecessary, but a general 

 one may be useful. At the top is an oyster bed 

 (Ostria caliijira) and below it dark clays and marls, 

 with Ccrithium plication, Corbula siib-pisum, and 

 Valuta Rathicri ; then come beds with Cytherea LyclUi, 

 Corbula Vecticnsis, and at their base sandy beds with 

 Ccrithium dedans, Cyrena scmistriata, and Rissca 

 Chastcllii, with much comminuted shell matter. These 

 beds make up the Corbula beds or top division of the 

 Hamstead strata. 



In the upper freshwater and estuarine marls (stiff 

 green marl) the most important fossil is a Cypris, 

 which occurs in a thin bed near the base. The 

 middle freshwater and estuarine marls contain plants 

 among which may be mentioned Equisetum, Nym- 

 ph?ca, and fruits which occur intermingled with 

 Cypris remains. At the base, the well-marked 

 "white band" full of Cyrena semistriata, Mclauia 

 fasciata, and largely made up of broken shells. Tlie 

 lower freshwater and estuary marls may be seen close 

 to the shore and sometimes on the strand, and 

 consist of dark clays and marls, with fairly abundant 



fossils, such as Hydrobia /nipa and Cyrena semistriata, 

 Mclania fasciata, Rissoa, fish remains, and wood. 

 At the base of these marls the well-known black band 

 was easily found, with its Paludina, Cyclas, and 

 Rissoa. While walking along the shore at low tide, 

 beneatli the exposures of the Hamstead beds we 

 picked up a few crocodile scutes, and turtle remains, 

 and much more rarely a fragment of Hyopotamus. 



Beyond the black band, going to the N.E. we 

 immediately came on the Bembridge marls, which 

 were exposed on the shore, as the east winds, which 

 had long prevailed, had cleared away the shingle. 

 They consisted mainly of stiff green and bluish marls 

 in certain zones crowded with beautiful shells, 

 among which we found three species of Melania, 

 M. Forhesii, M. turritissima, and M. mnricata, besides 

 Cyrena pulchra, C. obtusa, Melanopsis carinata. We 

 just pushed on to the Bembridge limestone, which 

 forms by its outcrop one of those dangerous ledges 

 which are so common in the Isle of Wight, and then 

 raced against the tide to secure specimens of the 

 characteristic fossils from tlieir best exposures, before 

 their site was again reclaimed by the envious sea. 



A heavy bag was carried back to Yarmouth after 

 this fairly full day's work, and what little of the day 

 remained was spent in sorting and naming the speci- 

 mens, and in recording an account of the section 

 worked through. 



The next day we resolved to start from Yarmouth 

 and work as far as possible towards Headon Hill, 

 intending to work out and tabulate the section as 

 carefully as we could, without spending much time in 

 collecting fossils except those which were absolutely 

 necessary for correlating the beds at the different 

 exposures. 



Going westwards along the shore and along the 

 military road we came upon some exposures of the 

 Bembridge limestone, a white tufaceous limestone, 

 where we collected a few fossils, such as Limnaa 

 longiscata, Buliinus ellipticus, Flanorbis discus, and 

 the round bodies called by the Survey turtle eggs. 

 Over the limestone some trace of the Bembridge 

 marls were found, having the same characters as at 

 Hamstead. 



Below this limestone, mottled green and reddish 

 clays and marls occur, with here and there a band 

 of comminuted shells and a very thin band of nodular 

 limestone. This is exposed at Cliff End, and on the 

 shore at low water may be found the highest beds 

 of the Upper Headon, which consist of dark clays 

 with Paludina lenta in fair preservation, and white 

 bands of smashed Potamomya gregaria, and in one 

 band the delicate freshwater Serpula tenuis. The 

 shore is there grass-grown down to the sea-wall for 

 some distance, and beyond, where the cliff is again 

 seen, a little of the mottled marls is to be seen at 

 the top and underneath the clay, with Paludina lenta 

 and Serpula tenuis, and below that, bands of clay 

 and a band of limestone, soft in situ, but forming 



