Prof. C. Lapicorth — Cambrian RocJcs at Nuneaton. 319 



on the strongest grounds of expediency, is therefore to be deprecated. 

 I am fully aware that Prof. Hebert is one of those who has adopted 

 Prof. Judd's nomenclature, but Prof. Hebert appears to shrink from 

 proposing a new name for the Lower (Neocomian) beds, though he 

 employs D'Orbigny's names for the other groups : consequently he 

 has only succeeded in introducing an element of confusion which did 

 not previously exist in the French nomenclature. 



The height of incongruity is reached when, by retaining the name 

 of Wealden for the fresh-water beds and adopting that of Neocomian 

 for all our marine beds, we have a Neocomian overlying the Wealden ! 

 and consequently applied to the very beds Marcou and Renevier have 

 so clearly and carefully distinguished from those strata which were 

 originally called Neocomian in Switzerland and the south of France 

 (see ante). I trust that I have now made it clear that to continue 

 the use of Neocomian, either as a synonym for Lower Cretaceous 

 or as a substitute for Lower Green sand, would be productive of 

 immense confusion, and would entirely stultify the work of two 

 of the principal authorities upon the beds in question. Neither does 

 it seem desirable to introduce the term Aptien into British nomen- 

 clature, partly because of the difference of opinion which exists in 

 France as to the relative extension of Aptien and Urgonien, and 

 partly because there is not sufficient continuity between the French 

 and English areas to make any correlation so safe and certain as it 

 is in the case of the Upper Cretaceous groups. The Cretaceous rocks 

 of England are now undergoing revision by the members of the 

 Geological Survey, and the desirability of formulating a new nomen- 

 clature will be considered when the work is farther advanced : the 

 merits of the name (Vectian) which I have already proposed as a 

 substitute for Lower Greensand will then be discussed ; at present I 

 am content to let it remain in abeyance. For my present purpose 

 the local names used for the groups in the Wealden area will serve 

 as a means of comparing the beds of southern England with those 

 of northern and southern France so far as is possible under the cir- 

 cumstances ; this is done in the following table : — 



South England. N.E. France. S.E. France. 



Folkestone and Sandgate Beds, j Sands and Sandstones. I A-^jp- 



Hythe Beds. Plicatula Clays. ) 



Atherfield Clay. The red band. Bhodanien. 



rFreshwater Beds. ) jj 



j The Oyster Clays. (Urgonien. 



Weald Clay. < Yellow MflrL 



I Spatangus Limestone Sands > Upper ) 

 I and Clay. ) j Neocomien. 



Hastings Sands. (Absent). Lower ) 



VI. — On the Sequence and Systematic Position op the Cam- 

 brian Rocks of Nuneaton. 

 By Prof. C. Lapworth, LL.D., F.G.S. 



IN the Geological Magazine for December, 1882, 1 I published a 

 brief note upon the " Discovery of Cambrian Eocks in the 

 1 Lapworth, Geol. Mag. 1882, Dec. II. Vol. IX. p. 563. 



