WESTLETON BEDS TO THOSE OP NORFOLK, ETC. 85 



shire, Kent, and Surrey. But that paper was only published in 

 abstract, and without tables or sections. 



In the meantime the significance of the>>e beds had not escaped 

 the attention of Mr. Whitaker, who adopted the name of the 

 *' Pebbly Series ; " but as there are very similar pebbly beds of 

 Tertiary age in the lilackheath, Addington, and Bagshot districts, I 

 think the local name of Westleton, where their typical characters 

 can be best seen, preferable. In 1880 * Mr. Whitaker came inde- 

 pendently very much to the same conclusion as myself with respect 

 to certain Pebble-beds on some of the hills around London, as 

 likewise did Mr. S. Y. Wood, who gave in his paper of 1880 t 

 a plate of sections and a map showing a number of outliers in 

 the London and Hampshire Basins, but with the drilt-cappings 

 marked in many instances doubtfully, and mostly without local de- 

 scriptions or proofs. I shall have occasion to refer to both these 

 papers at greater length presently. 



As regards classification, Mr. S. V. Wood, in his several papers 

 (1866-1872), places the Pebbly Sands of the Bure Valley at the 

 base of the Glacial Series (or of his " Lower Glacial ") ; whereas 

 Mr. H. B. Woodward, in his Survey Memoir, classes them with the 

 Upper Crag. It is true that in Norfolk they succeed immediately, 

 and in many cases conformably to the Norwich Crag and Chiliesfoid 

 Beds : but, as pointed out by Mr. Wood, there is also often a line of 

 erosion between the two, and although the marine fauna contains 

 similar species, it is poorer and more purely northern than that of 

 the Crag Series. Further the Pebble-beds extend far beyond the 

 area of the Crag, and afford evidence, as I shall endeavour to prove 

 presently, of great physiographical changes having intervened be- 

 tween these two groups. There is evidence also of an ecjually 

 important, if not a still stronger, break between the " Pebbly 

 Series '' and the Glacial Beds. I would therefore assign to the 

 Westleton Beds a position apart, whether in relation to the Crag or to 

 the Glacial Series. They mark a great change not only in the 

 physical geography, but also in the life of the times, for it was thin 

 that the existing Mammalian fauna began to supersede the extinct 

 species, and the Molluscan fauna to resolv(^ itself almost entirely 

 into species now common in this country, with a few others, which 

 although still living are, like some of the land animals, relegated 

 to colder climates. This applies also to tlie flora. 



For these reasons and also because this period is one of those coin- 

 cident, as I hope to show in the second part of this paper, with the 

 time of the final elevation of the Weald and of the genesis of the 

 Thames (the main excavation of the valleys and the great denudation 

 of the Weald being referable to subsequent Glacial and Post-Glaci:il 

 times), much importance attaches to tliis geological horizon. I also 

 look upon these beds as the base of the Quaternary Series. 



Since 1870 a number of important papers, including several 



* Mem. Geol. Survey, " Guide to the Geology of London and tlie Nei^^hbcnir- 

 hood," pp. of)-.")?. 



t Quart. Journ. Geol. Soc. vol. xxxvi. p. A'u. 



