RELATIONS TO OTHER BRITISH DEPOSITS. 59 



In England the lower cretaceous beds are developed under two 

 very different types, namely, the North British Type or Speeto- 

 nian, and the South British or Vectian. In Surrey, Sussex and 

 Kent the Vectian series is divided as follows : 



C. Lower Greensand. 



4. Folkestone Beds. 

 3. Sandgate Beds. 



(Upper Neocomian). 2. Hythe Beds. 



(Aptien). [ 1. Atherfield Clay. 



B. Weald Clay. 

 A. Hastings Sands. 



But this series, so well developed in the S.E. of England and in 

 the Isle of Wight, becomes greatly altered before it appears again 

 some 30 miles off along the coast in Swanage Bay, for in this place 

 the upper division or Lower Greensand is only with difficulty 

 recognisable and is greatly reduced in thickness, though according 

 to Mr Meyer all the zones are there present. Another interesting 

 peculiarity of this section is the intercalation of some fresh — or 

 brackish — water deposits in the midst of the Lower Greensand, 

 shewing the temporary recurrence of the earlier wealden con- 

 ditions in this area. Still further east we meet with the anoma- 

 lous and interesting silicious sandstone of Blackdown — the Black- 

 down beds ; and seeing that this rock contains a number of Lower 

 Greensand species, and that it lies exactly in the line of outcrop of 

 the Ironsand series, we might reasonably expect it to be nearly 

 related to these latter. But such an idea is decidedly overthrown 

 by a study of the fossils, for although both rocks are shallow water 

 formations, rich in organic remains, yet I only know of two species 

 common to the two deposits, namely, Cyprina rostrata and Pectun- 

 culas sublcBvis. 



The Ironsand series of Hunstanton-Farringdon, and the true 

 Vectian type of the Lower Greensand approach nearest to one 

 another in Berkshire and Surrey, and it is in these places that we 

 find, as already indicated by Mr Teall, the closest affinity between 

 the two types. By the careful work of Mr C. J. A. Meyer, F.G.S. 1 

 the series of sands, sandstones, limestones and clays in the country 

 around Godalming have been correlated with the complete series 



1 Proceedings Geologists' Association, read December, 1868. 



