104 Miscellaneous, 



He did not think that all such determinations rest upon the applica- 

 tion of observed coincidences of structure, for which coincidences 

 no reason can be rendered ; for, although in many instances of this 

 law of correlation, as demonstrated by comparative anatomy, the 

 sufficient or physiological cause of them is not known ; yet, in 

 other instances, the application of the principle has been suc- 

 cessfully illustrated. The truth or fact (said Prof. Owen) of a phy- 

 siological knowledge of a correlated structure, and of the applica- 

 tion of that knowledge to palaeontology, is not affected or de- 

 stroyed by instances adduced from that much more extensive series 

 of correlated structures of which the physiological condition is not 

 yet known. — Proc. Geol. Soc. Nov. 5, 1856. 



Note on Estheria minuta. By T. Rupert Jones, Esq., 



Assist. Sec. G.S. 



Not long since the Rev. W. Symonds favoured me with some well- 

 preserved specimens of this little Triassic fossil ; and, with Prof. J. 

 Quekett's kind assistance, I was enabled to see most distinctly the 

 true Crustacean character of the tissue of its valves. This confirmed 

 an opinion I had long held that this fossil is not a MoUusk, but 

 closely allied to the Limnadia, Limnetis, and Estheria *, bivalved 

 phyllopodous Crustaceans {Entomostraca) of the present day ; and 

 indeed, as far as the carapace-valves are concerned, it well represents 

 the Estheria of Riippell and Bairdf {Isaura, Joly). 



In the Quart. Journ. Geol. Soc. (1847) vol. iii. p. 274, Sir C. Lyell 

 figured a similar fossil from the coal-shales of Eastern Virginia, and 

 remarked that, with Mr. Morris, he doubted whether the so-called 

 " Posidonomya" may not be a Crustacean rather than a Mollusk %. 

 Similar fossils, of different species, occur in the Devonian rocks 

 (Caithness and Orkney), Carboniferous (Northumberland), Liassic 

 (Sky e and Gloucestershire), Oolitic (Scarborough), Purbeck (Dorset), 

 and Wealden (Sussex). Others are met with in the Jurassic Coal-fields 

 of North Carolina and Virginia §, and along their north-eastern ex- 

 tension, forming the so-called "New Red Sandstone" of Virginia 

 and Pennsylvania || ; in the plant-bearing sandstones of Central 

 India ^ (Nagpur and Mangali) ; and in the Triassic deposits of 

 Europe. 



* This is the little Triassic shell that has been termed Posidonia and Posido- 

 nomya minuta : Posidonia minuta, (Alberti) Goldfuss, Petref. Germ. p. 118. t. 113. 

 f. 5 ; Posidonomya minuta, Bronn, Leth. Geog. p. 164. t. 11. f. 22 ; Zieten, Verst. 

 Wurttemb. p. 72. t. 54. f. 5 ; Strickland, Geol. Trans. 2 ser. vol. v. p. 338. t. 28. 

 f. 4. In Morris's * Catalogue of British Fossils,' 2nd edit. 1854, it is included in 

 the Crustacea (as Estheria minuta) ; but (apparently from inadvertence) it has 

 not been expunged from the list of Mollusks in that work. 



t Proc. Zool. Soc. part 17. p. 86. 



% See also Lyell's * Manual of Geology,' 5th edit. p. 332. 



§ Lyell, loc. cit. ; and W. B. Rogers, Boston Nat. Hist. Soc. Proc. v. p. 15. 



II Continuous with the Sandstones of New Jersey, and most probably with 

 those of Connecticut also : Rogers, loc. cit. 



^ Quart. Journ. Geol. Soc. vol. xi. p. 370. 



