16 GEOLOGICAL MEMOIRS. 



Neocomian species of Echinoderms. On the contrary, as may be 

 seen by the foregoing Table, nearly all the species are found in the 

 Marnes d'Hauterive, both in the De'pt. de I'lsere, and in the French 

 Jura and Neuchatel ; and by consulting the works of Leymerie, the 

 same will be found to hold good for the Basin of the Seine. 



Thus are these Echinites found to indicate a particular geological 

 horizon ; the Marnes d'Hauterive of Switzerland and France corre- 

 sponding to the Hils-conglomerate of Germany. It seems indeed 

 that, even if some of the species occur in the lower Neocomian, none 

 of them passed up to a higher horizon than the Neocomian. The 

 only exception appears to be the occurrence of Toxaster complanatus 

 in younger beds up to the Upper Greensand in England (Morris's 

 Catalogue, 1st edit. p. 54*) ; but it is probable that this exception 

 will be set aside by further examination. The occurrence of this 

 species in the Speeton-clay is at least very doubtful. The Speeton- 

 clay of Brunswick does not contain anything of the kind. Either 

 the Speeton-clay of Yorkshire has not been separated from the lower 

 Neocomian, just as Phillips did not separate it from the Gault, or 

 , the Spatangus argillaceusy which Phillips figures from the Speeton 

 Clay, is a different species from Toxaster complanatusf. 



The agreement between the Marnes d'Hauterive and the Lower 

 Hils-conglomerate, as shown by their other organic remains, is thus 

 supported by an additional argument, — the identity of the Echi- 

 noideal fauna. But we must not forget that this same Neocomian 

 exhibits in different localities very different fades, such as Marcou 

 has described it at Nozeroy, and as it occurs in the Hartz. 



[E. Renevier and T. R. J.] 



On the Geology of the Northern Vorarlberg and the 

 Neighbouring Districts. By A. Escher von der Linth. 



[Memoires de la Societe Helvetique des Sciences Naturelles, vol. xiii.; and Bibliot. 

 Univ. de Geneve, Arch. Sc. Phys. et Nat. Sept. 1854, p. 67 &c.] 



The position of the Alpine rocks regarded as belonging to the 

 Keuper has been often the subject of discussion, especially since the 

 environs of S. Cassian in the Tyrol have furnished a large number 

 of fossils. M. Escher' s memoir treats especially of this difficult 

 subject, and contains also a description of the general succession of 

 the numerous rock-masses which constitute the eastern portion of 

 Switzerland and the western part of the Tyrol. The memoir is the 

 result of traverses made in this little-known Alpine region in 1851. 



M. Escher indicates in the following Table the order of the strata, 

 commencing at the top. This general view is established on the 

 numerous sections accompanying the memoir. 



* [This is corrected in the 2nd edit. 1854— T. R. J.] 



t [With regard to this species, the late Prof. E. Forbes remarks (Mem. Geol. 

 Surv. Dec. IV, t. 5. p. 4), " I can find no evidence whatsoever of the occurrence 

 of the true Toxaster complanatus in the British strata. Very distinct Sea-urchins, 

 members of no fewer than four different genera, have been intended by that name 

 in British hsts."— E. R.] 



