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 a])plication 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 j^alseoiatology, 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. Geo!. Soc. Nov. 5, 1856. 



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



Assist. Sec. G.S. 



Not long since the Rev. \V. 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 Mollusk, but 

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

 phyllopodous Crustaceans (Ejitomostraco) of the present day ; and 

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

 the Estheria of Ruppell and Baird f (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 

 (Skye and Gloucestershire), Oolitic (Scarborough), Purbeck (Dorset), 

 andWealden (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, (Albert!) Goldfuss, Petref. Germ. p. 118. t. 113. 

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

 "Wiirttemb. 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. Eogers, I3oston 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. 



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



