Geological Society. 523 



sandstone, Sir Philip Egerton says, it would be difficult, if not im- 

 possible, to define the proper limits of these formations. The new 

 red sandstone of England, the equivalent of the trias, presents this 

 difficulty, every endeavour to find the muschelkalk having failed ; 

 and therefore geologists are compelled either to consider the keuper, 

 the upper member of the trias, to be also wanting, or to be merged 

 in the mass of alternating marls and sandstones comprising the new 

 red series, Lithological structure, consequently, being of no value, 

 palseontological evidence, the author says, becomes of great import- 

 ance. The beautiful results arrived at by Mr. Owen respecting the 

 Batrachian remains found near Warwick, tend, Sir Philip Egerton 

 states, to render the existence of the keuper extremely probable, 

 though a specific identification with the analogous fossils of the 

 German keuper has not been ascertained. The only instances on 

 record of muschelkalk fishes found in Great Britain, are scales from 

 the Bone Bed at Aust Cliff, and referred by Professor Agassiz to 

 Gyrolepis Albertii and G. tenuistr talus, common continental muschel- 

 kalk fishes. This bed it is well known occurs at the base of the has, 

 and rests conformably on the green and red marls of the new red 

 sandstone. A thin stratum replete with remains of saurians and 

 ichthyolites occupies a similar stratigraphical position near Axmouth ; 

 and Prof. Agassiz, during his visit to England in the autumn of 1840, 

 identified in a series of specimens obtained by Miss Mary Anning, 

 one Placoid, two Lepidoid, and one Sauroid fish, with well-known 

 muschelkalk species. He also determined the existence of fifteen other 

 species from this deposit, none of which have been yet noticed in 

 the continental Triassic group. Two, if not three, of the above 

 muschelkalk ichthyolites are also found at Aust ; and a comparison 

 of the Aust and Axmouth species gives five as common to the two 

 localities, twelve as confined to the former, and two to the latter. 

 The only conclusion, Sir Philip Egerton states, which he feels justi- 

 fied in advancing from the facts adduced in this communication is, 

 that the beds in question, hitherto considered as belonging to the 

 lias, must be removed from that formation, inasmuch as they pre- 

 sent a series of fishes not only specifically distinct from those of 

 the lias, but possess in the Ganoid genera the heterocerque tail, 

 an organism confined to the fishes which existed anterior to the 

 lias. 



Appended to the paper is a systematic catalogue, compiled from 

 the • Poissons Fossiles,' of the Ichthyolites hitherto described, from 

 the keuper and muschelkalk of the Continent, together with those 

 recently discovered at the Aust Passage and near Axmouth. The 

 following extract from that document contains the species common 

 to the Continent and England : — 



Continental Localities 

 Order. Genus and Species. English Localities. and Formations. 



Placoid. Hybodus plicatilis. Axmouth. Passim. Muschelkalk. 

 Ganoid. Gyrolepis Albertii. Ibid. — Aust. Passim. Ibid. 



„ tenuistriatus. Ibid. — Ibid. Passim. Ibid. 



„ Saurichthys apicalis. Ibid. Bayreuth. Ibid. 



2M2 



