502 Von Koenen — Belgian Tertiaries. 



Sables de Braclieux being very small and little known, and bearing 

 a dij0ferent asjDect, it is not surprising that tbe correspondence in age 

 of the Sables de Bracheux with the lime-beds of Mons cannot yet be 

 proved by Palseontology, whereas Geology indicates it. 



Mr. Cornet has written me recently that he has since recognized 

 his error, and that he is going to rectify it. I have thought it 

 desirable to make this statement in order to save the honour of 

 Palaeontology, because Mr. Whitaker^ has cited the paper of Messrs. 

 Cornet and Briart as a proof that it is unsafe to trust to Palaeontological 

 evidence. 



I wish, in passing, to say a few words on the ferruginous sand- 

 stones from Kent, about which Mr. Whitaker 1. c. does me the 

 honour to cite my opinion. 



The commonest and best determinable fossil, or rather cast, in 

 Mr. Prestwich's collection was Area lactea, Lin., which I mistook at 

 first sight for A. pretiosa, Desh., a species peculiar to the Middle and 

 UpjDer Oligocene beds, but after careful examination, I recognized 

 that it was the recent species, and in this opinion I was confirmed by 

 the superior knowledge of the late Dr. S. P. Woodward. Besides 

 this species, I believe there were Terehratula grandis, Scalaria 

 foUacea, and Emarginula fissura, L., so that I thought it probable 

 that those beds corresponded with the Eed Crag, and in this the late 

 Dr. S. P. Woodward, one of the best judges of this matter, was also 

 of the same opinion. Unhappily I made no list of the determinable 

 fossils, but I hope Mr. Prestwich, who so kindly allowed me to 

 make gutta-percha casts from his specimens, will find them out 

 again, and confirm my statement. 



Mr. E. E. Lankester^ has published a paper " On the Tertiaries in 



the neighbourhood of Antwerp," by which he introduces into 



English literature the discoveries and observations made by Messrs. 



Nyst, de Wael, and Dejardin. He adopts the old division of the 



Antwerp beds, by Nyst, Dumont, etc, into : 



o j.» a ij- • ( Sable iaune. 

 bysteme bcaldisien. < c< 1,1 • 

 •^ ( Sable gris. 



Systeme Diestien. 



( Sable vert. 

 ( Sable noir. 



He calls the Systeme Scaldisien, Upper and Middle Pliocene ; the 

 Systeme Diestien, Lower Pliocene, not Miocene, (as I had published 

 it two years before), and he tries to prove the correctness of this 

 opinion by the per-centage of recent species in the different beds, 

 and by the resemblance of the fauna of the Systeme Diestien to that 

 of the Systeme Scaldisien, and of the Coralline Crag, after the lists 

 published by Mr. Nyst. Now the list of Mr. Nyst of the fossils 

 from the Systeme Diestien was not intended as a monograph, but 

 purely to illustrate a new locality, so that it is not extraordinary if 

 a number of names are erroneous. On the contrary, it is most 

 natural that Mr. Nyst should have identified the new-found fossils 



1 Quart. Journ. Geol. Soc., 1866, p. 432. 



2 Geol. Mag., 1865, pp. 103-6 aud 149-52. 



