1871.] TATE — NUBIAN SANDSTONE. 405 



tradietory nature ; indeed the generic names assigned to the fossils 

 seem to have been given in accordance with their presumed age as 

 determined by the lithological characters and physical conditions 

 presented by the containing rocks, rather than as interpretations 

 of zoological affinities. 



Thus the Encrinites which occur in the Nasb-valley limestone are 

 represented by fragments of cylindrical stems, and do not admit of 

 generic determination. The Ammonite, the only fossil mentioned 

 by Figari Bey, is not named specifically ; and I have reason to doubt 

 the correctness of its identification, and suspect that it may have 

 been either a Nautilus or a Goniatite. Mr. Etheridge and Figari Bey 

 have referred the fossils brought under their notice to Secondary 

 genera, Bncrinus and Ammonites ; whUst Mr. Salter assigned the En- 

 crinite stems to the Carboniferous genera Wiodocrinus and Poterio- 

 crinus, and adds to the list the Gasteropod genera MurcTiisonia and 

 Eulima (?), which latter are Triassic as well as Carboniferous. 



So that reaUy it has hitherto been difficult to express any very 

 decided opinion on the age of the Nubian Sandstone, owing to the 

 great want of palaeontological evidence. Conclusive evidence of the 

 Carboniferous age of the series, however, has been recently brought 

 to light. Captain Wilson and the Eev. F. W. Holland, of the Sinai 

 Ordnance Survey, have placed in my hands a block of limestone 

 from the Kasb-valley section (vide Bauerman, loc. cit. p. 26) in 

 the hope that it would yield evidence of its age, and so of the asso- 

 ciated sandstones. 



One fossil only, in a good state of preservation, was contained in 

 the mass ; this I at once named Orthis Michelini, a well-known 

 fossil of the Carboniferous Limestone ; but that the specific deter- 

 mination might be indorsed by the greatest authority on the fossils 

 of the class to which it belongs, and so acceptable as indisputable 

 evidence, I submitted the specimen to Mr. Thomas Davidson, who 

 obligingly writes, that the " inclosed fossil is certainly Orthis Mi- 

 chelini, as you correctly identify it." With this valuable index to 

 the age of the limestone, the obscure forms associated therewith 

 may be approximately assigned to the genera indicated by Mr. 

 Salter, who thereupon referred these beds to the Carboniferous 

 epoch. 



Mr. Salter * has moreover described a Lepidodendron from Sinai 

 as a new species, under the name of L. Mosaicum ; and though 

 neither the locality nor the stratigraphical position of the fossU was 

 known to him, yet, as it is preserved in sandstone, we cannot hesi- 

 tate in referring it to one or the other of the arenaceous members of. 

 the jS"ubian Sandstone ; and the Eev. F. W. Holland was fortunate in 

 obtaining a portion of a Sigillarian stem from the Wady Mokatteb, 

 which, though not collected in situ, bears unmistakable evidence 

 of having been enclosed in the sandstone forming its cliffs. The 

 sandstone in this valley is overlain by Cretaceous limestone, and is 

 presumably referable to the Upper Sandstone of the Carboniferous 

 series of this region. 



* Quart. Jouni. Geol. Sor. toI. xxiv. p. .509. 



