210 J. S. GARDNER ON THE LOWER LONDON" TERTIARIES. 



and interest. Every one admitted the great gap between the Chalk 

 and Thanet Sands, and that the Thanet Sands, Woolwich Series, and 

 Basement Beds were, like the " Landenian System " of Belgium and 

 the " Sables Inferieurs " of France, merely minor subdivisions of 

 one continuous formation, with variations caused by local subsi- 

 dences and elevations. He had recently found marine shells as far 

 west as Beading. The fluviatile Woolwich Beds pass at Heme Bay 

 into marine beds with a poor fauna. In Belgium and France these 

 beds contain a much larger marine fauna than our own. He thought 

 the actual facts did not support the views of the author. 



Mr. Whitaker stated that the separation of the Oldhaven Beds on 

 the Geological Survey maps was due to the fact that they were 

 clearly recognizable, and capable of being followed and mapped. 

 He found no reference in Mr. Gardner's paper to the fact that the 

 Oldhaven Beds are not always marine, but sometimes fluviatile and 

 fluvio-marine. He agreed that the apparent conformity of the Chalk 

 and Tertiary in England does not prove that there is no gap. Ho 

 had clearly recognized long ago that in Eastern Kent there is no 

 marked separation between the Thanet and the Woolwich Beds. 

 The three members of the Lower London Tertiaries are really very 

 small and insignificant subdivisions. He thought that the perfectly 

 rolled condition of the flint pebbles of the Oldhaven Beds pointed to 

 the conclusion that they were formed, not on a beach, but a little 

 way out at sea. The Woolwich Beds sometimes lie on eroded 

 surfaces of the Thanet Beds, which is opposed to the author's 

 views. So also, is the alternation of plastic clays with shelly 

 Woolwich Beds, which makes it impossible to divide the Beading 

 from the Woolwich Beds . He remarked on the local character and 

 distribution of the Oldhaven Beds as compared with the Woolwich- 

 and-Beading Beds ; in some places the former rest unconformably 

 on the latter, on the Thanet Beds, and on the Chalk. . 



Prof. Seeley remarked upon the important fact pointed out by 

 Mr. Sorby that the Thanet Sands were mainly derived from granitic 

 rocks. He thought the existing classification was a convenient one, 

 especially for teaching-purposes. He doubted the accuracy of the 

 general view supported by the author, namely that the materials of 

 these strata were derived from the west. He himself thought that 

 both palseontological and physical evidence pointed to the conclusion 

 that the materials were derived from the east. He doubted not 

 only the author's conclusions with regard to the climates of these 

 different periods, but all conclusions of the same kind. 



The Author stated that he had found a very characteristic flora 

 under the mottled clays of the Beading Beds, a flora also found at 

 Newhaven and in Greenland. He believed the mottled clays to be 

 purely freshwater deposits. These beds are traceable at Lewisham 

 and Blackheath under the Woolwich Beds. He maintained that 

 there is no means of comparing the faunas of the two beds ; but the 

 floras are dissimilar and show a marked climatal change. He did 

 not agree with Mr. Whitaker and the Survey that the Bromley 

 leaf-beds belong to an Oldhaven freshwater series, but thought 

 them to be on the same horizon as the Woolwich flora. 



