Geological Societij. 209 



some of which are known to feed upon such plants as we here find 

 them associated with in their fossil state, and others are well known 

 inhabitants of stagnant pools. 



Of the numerous plants, the few the author collected have been 

 examined by Mr. Lindley, who considers one to be undistinguish- 

 able from the recent Fraxinus rotundifolia, others strongly to re- 

 semble Acer opulifolium and A. pseudoplatanus ; and a specimen 

 of the leaf of an extinct poplar, remarkable for its form, has been 

 named by him Populus cordifolia. 



In conclusion the author infers, 



1st, That the deposit of CEningen is of purely lacustrine origin, 

 and that its formation must have occupied a protracted period. 



2ndlj', That the tertiary marine formation of the molasse, was 

 deeply excavated before the lacustrine accumulation commenced. 



Srdly, That, from the intermixture of species undistinguishable 

 from those now existing, with others which are decidedly extinct, 

 this deposit must be considered one of those instructive examples 

 which exhibit a gradual passage from an ancient state of nature to 

 that which now prevails. 



4thly, That, as it differs in most of its organic remains from all the 

 fresh-water formations hitherto described, either near to, or remote 

 from it, it must have been an independent deposit ; and judging 

 from its fossils and superposition to the molasse, it must have been 

 of recent origin. 



5thly, That recent as its origin may have been, the lacustrine 

 basin has since been re-excavated to a great depth through hori- 

 zontal strata of limestone, the highest of which are still seen six 

 hundred feet above the present bed of the Rhine. 



6thly, That although the deposit must have been formed long 

 before the Rhine occupied its present level, the organic remains 

 indicate, that even in those days there were insects, fishes, and plants 

 almost identical with our own ; and that among the quadrupeds there 

 existed one, undistinguishable from the common fox now inhabiting 

 our latitudes. 



Feb. 5. — James Calder, Esq. of Calcutta, and Edward Johnstone, 

 Esq., of Trinity College, Cambridge, were elected Fellows of this 

 Society. 



A letter addressed to the Secretary, R. I. Murchison, Esq. F.R.S. 

 was read, entitled, " On the animal remains found in the Transition 

 Limestone of Plymouth," by the Rev. Richard Hcnnah, F.G.S. 



Tills is the last of a series of communications by the author on 

 the same subject; and in this he endeavours to classify all the organic 

 remains found by him in the Plymouth limestone. In this arrange- 

 ment there arc enumerated several genera of Polyparia, including 

 Spongia?, Sty Una, Caryophyllia, Turbinolia, &c.; several species 

 of Crinoidca, and genera of Conchifera and Mollusca. 



After a detailed description of many species in each of the above 

 classes, the author concludes, that as the number of Zoophytes 

 bears a very large proportion to that of the Hivalves and Uni- 



N.S. Vol. 7. No. .S9. March 18.".0. 2 E valves, 



