466 Geological Society : — 



The work requires rather close reading in parts, and the arrange- 

 ment of the text, too crowded, militates in our opinion against an 

 enjoyable perusal of the text. But our view on these points must 

 go for what it is worth. The appearance of the work externally 

 and the type and apparently great accuracy in printing are all Al. 

 In an extra volume the Authors promise to treat of theory of 

 equations, integer analysis, symbolic methods, determinants and 

 groups, probabilities, and insurance, with a full index. Examples 

 accompany the text and conclude each chapter. 



LIV. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 



[Continued from p. 222.] 



January 26, 1887.— Prof. J. W. Judd, F.B.S., President, 

 in the Chair. 



THE following communications were read : — 

 1. "On the Correlation of the Upper Jurassic Rocks of the Jura 

 with those of England." By Thomas Roberts, Esq., M.A., F.G.S. 



The author described at length his observations on the rocks of 

 the Jurassic system, from the Callovian to the Purbeckian inclusive, 

 first in the Canton of Berne and then in the more southerly Cantons 

 of Neuchatel and Vaud. The sections in the former differed ma- 

 terially from those in the latter, and the following stages and sub- 

 stages were observed : — 



North District. South District. 



Purbeckian. Purbeckian. 



Portlandian. Porhlandian. 



Virgulian. ? 



Pterocerian. Pterocerian. 



Astartian. Astartian. 



(Calcaire a Nerine^es. 



Oolithe Corallienne. 



Terrain a chaillessiliceux. Corallian. 



~ „ ,. f Terrain a chailles marno-calcaire. Pkoladomian. 1 ^ « -,. 



Oxfordian. j 0aloaipe , Seyphieg infer ieur. Spongitian. } 0xfordian - 



~ ,. . f Le fer sous-Oxfordien. Superieur. p ,, . „ 



Callovian. j Zone of Am _ macrocepha i us . Inferieur. 



-r, ,, . f Dalle nacree, &c. Dalle nacree. 



Batnoman. 



Some of the lithological and palseontological differences between 

 these rocks and the English Oolites were noticed, and the views of 

 Oppel, Marcou, Waagen, Blake, and Renevier, as to the relations of 

 the beds in the two countries, were commented upon. The Author 

 then proceeded to compare the fossils of the Swiss Jurassic beds 

 with, those of their English representatives, stage by stage, and 

 finally suggested the following correlation : — 



