262 Notices of Memoirs — R. Bullen Newton — 



Pelecypoda. Tapes perovalis. 



Area lactea (?). Lutraria elliptica. 



Pecten avicida(?) and P. bruei. Crassatella concentrica (?.)', Duj. 



Modiola modiola (?). Tellina donacina (?) or Donax. 



Pectunculus glycymeris ('?). Mactra triangulata (?) . 



Nticula nucleus (?) . Cardita, Luciyia or Diplodonta, Kellia 



N. depressa, Nyst. or Lepton, Isocardia. 



Leda lanceolata and L. myalls (?). Venus (?), Anatina, Panopcea (?). 

 Astarte digitaria, A. pygmcea, A. 



compressa (?) , A omalii{?). BRACHIOPODA. 



Cardium (with spines) and C. edule. Terebratula grandis (?). 

 Cytherea rudis (?) . 



In the same memoir Prestwich referred to the occurrence of 

 similar ferruginous sandstones to those at Lenham on the chalk downs 

 between Calais and Boulogne, and at Cassel Hill in French Flanders, 

 515 feet above the sea, overlying the Caleaire Grossier series. It Avas 

 mentioned that such beds, although without fossils, had been deter- 

 mined by Dumont and Lyell as equivalent to the Diestian Sands of 

 Belgium, which they classed with the English Crag, because the same 

 sands had been found at Louvain overlying the Limburg and Bolder- 

 berg strata, containing impressions of shells of Terebratula grandis, 

 Solen ensis, and Syndosmya prismatica, besides thirteen genera of 

 indeterminable species. In a further reference to the Lenham 

 Mollusca, Searles Wood l mentioned that the Pyrula and Pectunculus 

 resembled certain sandstone casts from the lied Crag (Box-stone 

 specimens), although a closer determination was not possible from 

 their peculiar preservation. 



Lyell 2 recognized the Lenham Beds as of Upper Miocene or 

 Falunian age, and similar to the Diestian Sands of Belgium, and, 

 moreover, probably older than the Coralline Crag. 



He had traced the Diestian beds, which "abound in green grains ", 

 from Diest by Louvain and Oudenarde to Cassel in French Flanders 

 and capping the hills of those places — away to the English Downs 

 near Folkestone, and appearing at such places as Paddlesworth, 

 Lenham near Maidstone, etc. He referred to the occurrence in 

 those beds of Terebratula grandis, casts of Astarte, Pyrula, Emarginula, 

 which were all common to the British Crag, the first-named being 

 specially characteristic of the Belgian Diestian. 



As a result of an examination of the Prestwich Collection and that 

 of the Geological Survey, Yon Ivoenen 3 was of opinion that Lyell 

 was wrong in his estimate of a Miocene age for the iron-sandstones 

 of Kent, he regarding them as Pliocene because he considered they 

 contained characteristic shells of the Upper Crag. 



Mr. Whitaker 4 next gave his opinion on the age of the Lenham 

 fauna, assisted by Gwyn Jeffreys in connexion with the molluscan 



1 " On the Extraneous Fossils of the Red Crag " : Quart. Journ. Geol. Soc, 

 vol. xv, pp. 32-45, 1859. 



2 Elements of Geology, 6th ed., pp. 233, 368, 1865. 



3 "Die Fauna der Unter-oligocanen Tertiarschichten von Helmstadt bei 

 Braunschweig" : Zeitsch. Deutsch. Geol. Ges., vol. xvii, p. 461, 1S65. 



4 "On the Lower London Tertiaries of Kent" : Quart. Journ. Geol. Soc, 

 vol. xxii, p. 430, 1866. 



