146 PKOF. J. W. JXJDD ON THE OLIGOCENE 



slight dislocations and a small series of contortions. At Totland 

 Bay there is undoubted evidence of the presence of a slight anti- 

 clinal 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. The great mural face of Headon Hill, however, has a trend 

 almost at right angles to that of the cliffs of Colwell and Totland 

 Bays ; and the section exposed on the face of the hill is nearly at 

 right angles to the second series of flexures which have been indi- 

 cated as afl'ecting the Isle-of-Wight beds. These strata seen in 

 Headou Hill have a slight dip to the west. Passing round Heather- 

 wood Point we again find the cliffs assuming a northerly and southerly 

 trend, and the beds are found dipping to the north, at an angle which 

 increases very rapidly, till at Alum Bay the strata assume a ver- 

 tical position, and near the Chalk are for a short distance actually 

 inverted. 



I^ow, when these Isle-of-Wight cliffs are viewed from the sea, 

 the great changes which take place in the trend of the coast may be 

 easily overlooked ; and undoubtedly the first impression which is 

 made upon the mind of an observer is, that there exists a great anti- 

 clinal flexure, the summit of which is seen in Totland Bay, and that 

 the Colwell-Bay and Headon-Hill beds respectively lie in equivalent 

 positions on either side of this axis, and are therefore representatives 

 the one of the other. 



If, however, instead of trusting to the general impression which 

 is produced by viewing these beds from a distance, we carefully plot 

 the section to scale by the aid of the admirable 2o-inch maps of the 

 Ordnance Survey, allowing carefully for the changes in direction of 

 the cliffs, we shaU find that the effect produced by the Totland-Bay 

 anticlinal has been very greatly overrated, and that, in consequence 

 of this, the true order of succession of the beds has been altogether 

 misunderstood. The strata of How Ledge and Warden Point are 

 seen in such a true-scale section (PL YII. figs. 1, 2, & 3) to be clearly 

 continued in precisely similar beds appearing underneath the gravel 

 of Headon HiU ; the clays beneath are found to be a continuation 

 of those seen in Totland Bay ; while all the underlying strata are 

 recognized as distinct from and on a lower horizon than those ex- 

 posed in the bays to the north of Headon Hill. 



When we come to compare the succession and thickness of the 

 several strata exposed in Headon Hill and in the bays to the north- 

 wards, the correctness of this new reading of the section wiU become 

 strikingly apparent. The two series of beds can only be correlated 

 with one another, as has been attempted by previous observers, by 

 sux^posing that in the distance of a mile or two the most remarkable 

 changes have taken place, both in the mineral character and the 

 fossil contents of the several beds. But if, on the other hand, we 

 admit that the lowest beds in Totland Bay are represented in the 

 higher part of the Headon-Hill section, while the main part of the 

 strata at that localify are on a different and lower horizon, the dif- 

 ficulties and discrepancies will at once disappear. 



Fortunately, however, I am able to adduce proofs of the most 



