132 PROCEEDINGS OF THE GEOLOGIC AT^ SOCIETY. 



several new species, including tlie fine large Cyprina Scutellaria, the 

 Pectunculus terehratularis and Cardiiim Phimsteadiense, and some 

 peculiar fossil woods, make their first appearance in the Woolwich 

 group. The Corbula Regtdhiensis, which is comparatively rare in the 

 Thanet Sands, becomes also most abundant in places. 



This fauna is, in East Kent, confined to the lowest bed of the 

 Woolwich series. The upper beds are unfossiliferous, with the 

 exception of the rare occurrence of the small fragments of the 

 Myliobates, Edaphodoii, and Chelonia. As we approach London, 

 however, the middle and upper members of this deposit become well 

 marked by their organic remains. Of the marine fauna of Heme 

 Bay, the Corbula Regulbiensis, Nucula fragilis, Cardlum Plum- 

 steadiense, and Pectunculus terebratidaris (y iir. Plumsfeadiensis), occur 

 at Woolwich and Bromley, whilst in addition to this group we have 

 the remarkable local development of those estuarine and more fresh- 

 water forms, — the Cyrena, Paludina, Melania, Melanopsis, Planorbis, 

 JJnio, and Neritiva. These latter forms prevail more especially in 

 the centre of this division, in that portion of it so well exhibited at 

 Woolwich, extending beneath London on one side, and stretching to 

 Upnor on the other. Above these Woolwich clays in the same 

 central area are beds with a more estuarine fauna at first, but 

 showing as they pass upwards conditions still more freshwater than 

 those which prevail in the beds beneath. To this upper part of the 

 series belong the Paludina-limestone and the Unio bed at New Cross. 

 As this series trends towards Loudon all the members of it disappear 

 and are replaced by mottled clays and sands, the W^oolwich clays 

 being alone prolonged, and forming beneath London a single fos- 

 siliferous zone distinctly intercalated between two masses of the 

 mottled clays (see Well-sections, Appendix) . This is shown in the 

 sectional Diagrams A & C, PI. I. ; but to the south of the line here 

 intersected we find another zone of the Cyrena, Melania, and Ostrea, 

 intercalated on a higher level with these mottled clays, and of which 

 examples are found in the sections at Balham Hill, Wandsworth, 

 and Mitcham (Appendix). It is only by connecting these beds by 

 underground sections that the probable position of the well-known 

 Sundridge, Bromley, and Chiselhurst beds may be inferred ; for, 

 owing to the want of siirface-sections, no direct coimection can be 

 established between the beds of the Woolwich and Sundridge pits ; 

 but if we pass round by London, Clapham, Wandsworth, IMitcham, and 

 Croydon, we find this upper zone, at first only slightly developed, 

 assuming as it trends southward and then south-eastward an increased 

 importance, and eventually expanding and replacing the upper group 

 of sands and mottled clays, whilst on the contrary the underlying 

 lenticular mass of Woolwich clays thins out and is replaced bj' mottled 

 clays, so that this division then presents a large development of 

 mottled claj-s below, with shelly estuarine clays, limestones, and con- 

 glomerates above. I believe that the insulated shell-bed at Guildford 

 belongs to this upper series. Here, as before mentioned, the tr.ices 

 of animal life are confined merely to a thin snperjiosed layer. Beyond 

 both to the westward and northward, the great bulk of the sands and 



