334 MR. r. W. HAEMER Olf THE LENHAM BEDS [Aug. 1 898, 



elusion I agree entirely. The mollusca obtained from the boxstones, 

 although not identical with those from Lenham,^ are generally of a 

 similar character, including ConiLS JDujardinii,^ Nassa conglobata, 

 Yoluta auris-lej)07'is, and Isocardia lunulata (characteristic fossils 

 of the Miocene deposits of the J^orth Sea, or of those which I regard 

 as to some extent representing them, namely, the Pliocene deposits 

 of the Mediterranean), associated with other forms of a more modern, 

 but still Coralline Crag type. 



The marine vertebrata of the nodule-beds include also a similar 

 admixture of Miocene and Pliocene forms, as, for example, Herpeto- 

 cetus sccddiensis^ HopJocetus crassidens, and Squalodon antwerpiensls, 

 said to occur in the Bolderien deposits of Antwerp together with 

 species of Diestien age.^ 



Thus the boxstone fauna seems to be much of the same inter- 

 mediate character, between those of the Miocene of Belgium and 

 of the Coralline Crag, as is that of Lenham ; and I am iDclined to 

 agree with Prof. Eay Lankester that it is from a former extension 

 of a deposit of similar, though possibly not identical age, that the 

 boxstones and some other extraneous fossils found in the nodule- 

 beds have been derived.* 



The stratigraphical evidence lends, I think, some support to this 

 hypothesis. It has been often pointed out that the Lenham Beds 

 are connected by a chain of outliers with the sands of Louvain and 

 Diest, and they are probably contemporaneous with some part of 

 them. The upheaval which has affected these deposits has been 

 greatest in Kent, where they occur 620 feet above the sea-level ; 

 but their height becomes gradually less, until at Louvain it is barely 

 200 feet. They have been everywhere extensively denuded, except 

 east of Louvain (see map, fig. 1, p. 316), where they cover the 

 country with a continuous sheet ; but they dip towards the north- 

 west, and beyond Malines disappear under newer beds. 



Since the publication of my paper on the Pliocene deposits of 

 Holland, an important communication from the pen of M.Eutot, the 

 distinguished Belgian geologist, has appeared,' with maps showing the 

 probable extension of the I^orth Sea over Belgium at the commence- 

 ment and to"wards the end of the Diestien period ; the boundaries 

 there given I have reproduced in the accompanying map (fig. 1) by 

 the kind permission of M. Butot. That to the south indicates the 

 southern margin of the sea in which an earlier part of the formation, 

 namely, the sands of Louvain and Diest, zone a Terehratula grandis 

 (and, as I think, of Lenham), originated, and that to the north the 

 limits of the basin of the later portion, the zone a Isocardia cor. 



As the earth-movements which affected Holland and Belgium were 



^ The Lenham fauna must have contained many species wliich are not at 

 present known from that locality. 



2 Conus Dujardinii occurs also in the older portion of the Diestien beds 

 of Belgium (zone a TerehratvAa grandis). 



^ Van den Broeck, ' Esquisse Geol. & Paleont. des Depots Plioc. d'Anvers,' 

 pp. 68 & 120. 



* Quart. Journ. Geol. Soc. vol. xsvi (1870) p. 501. 



^ ' Les Origines du Quaternaire de la Belgique,' Mem. Soc. Beige de G6ol. 

 vol. xi (1897) p. 1. 



