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PEOCEEDINGS OF THE GEOLOGICAL SOCIETY, [Marcll 20, 



Wealden, one is constantly brought face to face with these four 

 genera ; they come in, as is well-known, soon after the commence- 

 ment of the Purbeck strata, and continue to appear at intervals up 

 to the base of the Neocomian, and, as I suspect, to a much higher 

 level. The species change somewhat in time, as do the species of 

 Cypris and Paludina, with which they alternate ; but there they are. 

 The reason, as I take it, is that throughout the period they never 

 Avholly left the Wealden area ; they are of no value in point of evi- 

 dence. 



The third group includes a set of species common enough in the 

 Neocomian beds of Atherfield and Shanklin, and some of them even 

 yet more common in Kent and Surrey ; of these the following have 

 been determined : — 



Corbula striatula, Sow. 



Pholadomya semicostata, Ag. 



Pholadidea. 



Teredo. 



Venus. 



Tellina vectiana, Forbes. 



Astacoid remains (in the clay at the 



base of the section and in the lower 



shell-bed). 



Ammonites Deshayesii, Besh. 

 Natica Isevigata, Besh. 

 Exogyra Tombeckiana, V Orh. 

 E. Boussingaultii, B' Orb. 

 E. sinuata, Sow. 

 Anemia lajvigata, Sow. 

 Plicatula asperrima, B'Orb. 

 P. Carteroniana, B Orb, 

 Cardium impressum, Besh. 

 C. subhillanum, Leym. 



What, then, is the true bearing of the evidence to be obtained at 

 Punfield in regard to these Punfield strata ? The physical evidence, 

 though inconclusive, certainly does not favour the idea of their corre- 

 lation with the Wealden beds of Atherfield or Surrey. The lower beds, 

 from the ironstone band to the "marine band" inclusive, are cer- 

 tainly marine, and contain no freshwater fossils : the middle and upper 

 beds bear traces of having been accumulated under the influence of 

 fluviatile action, but are in other respects undoubtedly marine. The 

 "grey Cypridiferous shales" a few feet only in thickness, which I 

 could not find, but which are said to come in at the top of the Pun- 

 field beds, are, to my thinking, of very little importance, and for 

 this reason, that they are no more than proof positive of the exist- 

 ence at tills point of fluviatile action, indistinct traces of which are 

 so commonly apparent in the Neocomian beds at Shanklin. 



The palaeontological evidence obtainable at Punfield, although also 

 to some extent contradictory, appears to me to be most strongly in 

 favour of the correlation of these strata with the Lower Greensand, 

 and not with the Wealden. Mr. Judd is no doubt correct as to the 

 age of these Punfield beds of Punfield ; I cannot possibly agree with 

 him in placing them beneath the Neocomian beds of Atherfield. 



To the author of this paper the so-called " Punfield formation " 

 of the Isle of Purbeck is Lower Greensand and nothing else. The 

 Punfield formation of the Isle of Wight is simply Upper Wealden. 



The occurrence of a Spanish fauna at Punfield proves, if it proves 

 any thing, that the Neocomian (Lower Greensand) series of the south- 

 east of England and of Eastern Spain are, in point of age, equivalent 

 deposits. 



The accompanying sections (fig. 1) illustrate, somewhat roughly. 



