Rev. A. Irving — Outlier of Upper BagsJiot Sands. Ill 



Not so much, reliance, however, can be placed on the actual species 

 as on the general facies in this case. The Landenien Inferieur beds 

 contain 12 species of Pleurotoma, 1 Valuta, 6 Natica, 5 Cerithium, 2 

 Turritella, 2 Solarium, 2 Area, 2 Crnssatella, 1 Nautilus, 1 JVecera, etc., 

 a fauna quite unlike that of the Thanet beds. 



Wherever the Landenien Inferieur comes in contact vi^ith the 

 underlying Heersien beds in the many sections I have seen, I have 

 not noticed a true unconformability, though there is occasionally an 

 overlap. The sand is sometimes coarse, otherwise the passage, from 

 a stratigraphical point of view, is quite conformable. When the 

 Landenien beds rest on the Calcaire Grossier de Mons, or on the 

 Cretaceous beds, there is in the former case generally a pebble bed 

 at the base, and in the latter green -coated flints, the same as we 

 see in the London Basin. This bed of green-coated flints is present 

 wherever the Tertiaiy beds, Heersien and Landenien, touch the 

 Cretaceous. It is seen also in many parts of France occupying the 

 same position. 



With respect to the Landenien Superieur beds of Belgium, they 

 are generally regarded as the equivalents of our Woolwich and 

 Reading beds. The only places in Belgium where molluscs from the 

 Landenien Superieur beds have been met with are in the artesian 

 wells at Ostend and Ghent. There are only nine species of fossils 

 in all. These are Melania inquinata, Melanopsis buccinoicles, Ceri- 

 thium funntum, Ostrea heUovucina, 0. tenera, Cyrena cuneiformis, G. 

 antiqua, Mijtilus, sp., and Ciiona erodens. The Landenien Superieur 

 beds are so deeply seated when fossiliferous, that it is with great 

 difficulty that they can be identified when they crop out at the 

 surface. The only fossils I have met with from them in an outcrop 

 is a piece of silicified wood and tubes of Annelides. I may mention 

 that the general character of much of the Landenien Superieur beds 

 in Belgium is such as to cause some geologists there to think it not 

 only fluvio-mariue or freshwater, but marine. 



I regard the greater part of the Landenien Superieur beds as 

 being part of the Landenien Inferieur, for reasons I will not enter 

 upon now. 



VI. — An Outlier of Upper Bagshot Sands on London Clay. 

 By the Eev. A. Irying, B.Sc, B.A., F.G.S. 



ri^HE chief object of this paper is to describe an unmapped outlier 

 JL of Bagshot Sand, in which the pebble-bed, frequently met with 

 at this level,^ exhibits an extraoi'dinary thickness and compactness. 

 It is situated at Bearwood, on the estate of John Walter, Esq., who 

 has kindly given me every facility for investigating it. The extent 

 of the outlier may be said to coincide approximately with the space 

 enclosed within the 250 foot contour-line of the Six-Inch Ordnance 

 Survey Map. On the south side it extends a little way to the 

 south of that line, in the form of several spurs forming low ridges, 

 the principal of which is crossed, and partly cut through, by the main 



1 See Proceedings of Geol. Assoc, toI. viii. pp. 149 — lol ; Q.J.G.S., vol. xli. 

 (Aug. 1885), p. 508 ; Proc. Geol. Assoc, vol. ix. pp. 219, 223, 224. 



