86 



H. KEEPING AND E. B. TAWNEV ON THE BEDS AT 



Wo conclude therefore that no reason has been shown for upsetting 

 the classification of the strata adopted by the Geological Survey, and 

 which, for nearly a quarter of a century, has been received among 

 geologists. 



Certainly we wish to uphold in its integrity the work of the late 

 E. Forbes *, and the classification of beds adopted by him when 

 Palaeontologist to the Geological Survey, and subsequently confirmed 

 by Mr. H. W. Bristow, E.B.S., in the second Survey Memoir f on the 

 Isle of Wight. 



One of the authors, from his long residence in the district and his 

 constant occupation with these beds, has been long satisfied that 

 E. Eorbes's account of the beds is true to nature, and his classification 

 fully borne out by lithological identity of beds, as well as by distri- 

 bution of the fossils. The present notes, then, are based on his part 

 upon an aquaintance with the district, and the work of the Geological 

 Survey there during its progress, supplemented by subsequent visits, 

 and specially this summer by a joint examination by both, including 

 measurement of beds and collection of fossils, which, however in- 

 complete, was made bed by bed, and represents the prevailing fauna 

 of each — a point on which we lay great stress. 



We do not wish to delay over the history of previous opinion, 

 which has been sufficiently treated in Eorbes's and Prof. Judds 

 memoirs ; but the latest criticism of Eorbes's work (op. cit. p. 141 ) 

 may be alluded to. 



II. TOTLAND AND Co DWELL BAYS. 



The Survey Horizontal Section east of Headon Hill. — The first 

 point at issue between Eorbes supported by " nearly all observers, " 

 on the one hand, and Prof. Judd on the other, is whether certain 

 marine beds known as the Middle Headon (including the " Venus-bed " 

 of local collectors) in Colwell Bay are rightly associated with similar 

 marine beds in Headon Hill. The Survey identify them, and 

 correlate the freshwater beds immediately above and below as Upper 

 and Lower Headon respectively in both localities. This succession, 

 however, is stigmatized (op. cit. p. 142) as a " mistake " of which the 

 " primary cause " is considered to be an " assumed " existence " of 

 a great anticlinal fold of which the summit is supposed to be seen 

 in Totland Bay. The manner in which this supposed anticlinal is 

 regarded as having affected the strata is illustrated in Prof. E. Eorbes's 

 memoir, pi. vii. fig. 1, and also in Sheet 47 of the Horizontal Sections 

 published by the Geological Survey. And yet further on we read 

 (op. cit. p. 146), " at Totland Bay there is undoubted evidence of the 

 presence of a slight anticlinal fold having its summit near Widdick 

 Chine, to the westward of which the beds for a short distance have 

 a slight dip to the south ; " so that after all the only mistake the 

 Survey could have made would have been to exaggerate the dip. 



We are next told of the E. and W. flexure, which causes a slight 



* On the Tertiary Flnvio-marine Formation of the Isle of Wight, by Prof. 

 E. Forbes. F.E.S., 1856 [Memoirs of the Geological Survey of Great Britain], 

 t The Geology of the Isle of Wight, by H. W. Bristow [Sheet 10], 1862. 



