110 



GEOLOGY OF THE ISLE OF WIGHT. 



fully displayed, are conspicuous objects in the cliff, where ihey 

 project out of the softer strata, and on the shore, owing to their 

 black and coal-like appearance. 



At the time of our survey these beds of coal were more than 

 usually well displayed in consequence of the prevalence of long 

 continued wet weather having worn away the soft intervening 

 strata in which they are imbedded. On examining them during 

 a brief visit made to the Ishind. in company with Sir A. Ramsay, 

 during the autumn of 1860, it appeared evident that the beds in 

 question occur in the manner of ordinary coal. Like true coal, 

 each bed was based upon a stratum of clay, containing, apparently, 

 the rootlets of plants, as in the underclay of the Coal Measures. 

 The underclays, which occur beneath beds of coal of Carboniferous 

 date, are thought to have been soil that supported the vegetation 

 which, by certain chemical changes, became subsequently converted 

 into coal : it is reasonable, therefore to infer from the presence of 

 similar underclays beneath the coal in the Bracklesham Beds at 

 Alum Bay, that the plants out of which that coal was formed grew 

 on the spot, and were not drifted from elsewhere, as was the case 

 with the vegetable remains in the pipe-clay beds of the Lower 

 Bagshot Series. 



A similar underclay was visible in Whitecliff Bay in December 

 1886, but, owing to the coal having been worked a few years 

 before as far as it could be conveniently reached, the seam itself 

 could not be examined or measured, though a sketch of the 

 roots was made. 



On comparing the section of the Bracklesham Beds in White- 

 cliff Bay with tlie corresponding section in Alum Bay, it will be 

 seen that the beds are much better developed in the former 

 locality than in the latter. It is, therefore, at the eastern ex- 

 tremity of the Island that these deposits may be studied to the 

 most advantage. Indeed, this is the only locality in the country 

 where the entire series can be seen exposed to view. The follow- 

 ing section is taken from Mr. Fisher's paper.* 



Section of the Bracklesham Beds at Whitecliff Bay, 



No. I. is the lowest of the series occurring towards the south end of the 

 Bay, and No. XIX. the highest of the series further to the north. The 

 letters ah c, &c., denote the more important fossil-beds. 



* Quart. Journ. Geol. Soc, vol. xviii. p. 67. 

 t Ibid., vol. ii. p. 223. (1846.) 



(1862.") 



