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THE GEOLOGIST. 



tkcy vary very considerably in different regions, they are best defined by 

 the word Permian, which, according to its original definition by himself 

 and his associates in Russia, simply means that such rocks lie between the 

 upper coal, on which they rest unconformably, and the lowest portion of 

 the Trias, by which they are covered. 



It was observed that, in proceeding from north to south (in eastern 

 Germany), the Zechstein thins out ; and seeing the vast dimensions which 

 the group assumes where true Zechstein is no longer traceable, the author 

 suggests that some of the higher members of the Bohemian Rothliegende 

 may represent that limestone in time. The term Dyas, recently applied 

 to the whole Permian group by G-einitz, is objected to, since it is based on 

 the theory that the lower portion of the Permian is exclusively of fresh- 

 water origin, as contrasted with the superjacent marine Zechstein, and also 

 because the geographical term Permian, involving no theory, had pre- 

 viously been widely adopted, and even used by G-einitz himself. 



Sir Roderick having expressed his great obligations to Dr. Geinitz, to 

 whose excellent work (' Dyas ') he made many references, and to the name 

 of which only he objected, concluded by presenting to the Society a very 

 large collection of rock specimens of the Lower Permian of Saxony. 



March 18. — 1. " On the Correlation of the several Subdivisions of the 

 Inferior Oolite of the Middle and South of England." By Harvey B. 

 Holl. M.D., F.G.S. 



The order of succession of the subdivisions of the Inferior Oolite ob- 

 served in passing from the southern side of the Men dips to the typical 

 section of that formation at Leckhampton, with the lithological characters 

 of the strata, were described in this paper. The classification of the mem- 

 bers of the Inferior Oolite employed by. Mr. Hull in the Memoirs of the 

 Geological Survey, was adopted by the author ; and it was shown that in 

 proceeding from Bath northwards, the two upper subdivisions may be seen 

 to rise, the building-freestone at the same time becoming thicker, while 

 at Aveling the Oolite marl is first seen interposed between the lower 

 ragstone and the lower freestone, and at Nailsworth the former is sepa- 

 rated from the Oolite marl by the upper freestone, all these beds be- 

 coming thicker towards Cheltenham, and thinner in the opposite direction, 

 towards Bath. Dr. Holl concluded with some remarks on the strata exhi- 

 bited in the Rolling Bank Quarry, and on the geographical distribution in 

 England of the members of the Inferior Oolite. 



2. " On the occurrence of large quantities of Drifted Wood in the 

 Oxford Clay, near Peterborough." By Henry Porter, M.D., F.G.S. 



The Oxford Clay in the neighbourhood of Peterborough having been 

 exposed in clay-pits, the author was enabled to carry on some investiga- 

 tions regarding the fossils which there occur in it ; he found the formation 

 to be extremely rich in organic remains, and, besides containing many 

 species of Ammonites and other Mollusca, which he enumerated, to include 

 large quantities of drifted wood, the fragments bearing on their surface 

 the impressions of Ammonites. 



3. "On a new Macrurous Crustacean from the Lias of Lyme Regis." 

 By Henry Woodward, Esq., F.Z.S. 



A very perfect specimen of a Crustacean, obtained from the Lias of Lyme 

 Regis by Mir. Harrison, of Charmouth, was described in this paper as the 

 type of a new genus. The nearest living analogues were stated to belong 

 to the fossorial group Thalassinidse, from which it differs chiefly in its 

 much less rudimentary abdomen, and the length of its chelae. Amongst 

 fossil forms, this Crustacean, which was named Scapheus ancylochelis, ap- 

 proached most closely to Megaclieirus longimanus, from the Solenhofen 



