Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/552

406 I append a list of the organic remains from the "Nubian Sandstone" series:—

[The sign ! prefixed to the names of the fossils indicates that the specimens were collected by the Sinai Survey; and the sign * indicates the determination of Mr. Salter.]

In conclusion I venture to suggest that the Adigrat Sandstone in Abyssinia, described and so named by Mr. W. T. Blanford, is of the same age as the Nubian Sandstone. It appears to have escaped the notice of that author that the Sandstone of Adigrat is similar in character and general appearance to the Nubian Sandstone, and that it, moreover, overlies the schistose rocks in the same manner, and contains iron-ore and psilomelane, as in Sinai. Mr. Blanford surmises, however, that "both the coal-bearing beds of Chelga and the Adigrat Sandstone may belong to a portion of the great series associated with [Triassic] coal in India" (loc. cit. p. 175); but the Talcheer and other coals are referred by Messrs. Blanford and Theobald to a Permian age (Mem. Geol. Surv. India, vol. i.).

.—My attention has been called since the reading of this paper to Prof. Unger's observations on the Fossil Wood from Assuan and Um-Ombos, in the Nile valley (Quart. Journ. Geol. Soc. vol. xv. Misc. p. 13, 1859). The wood belongs to, a coniferous tree of the Araucarian division, and is named Dadoxylon ægyptiacum; its habitat is assumed "to be the sandstone, which occurs extensively in Upper Egypt and Nubia, between the granite and Cretaceous beds," in which case Dadoxylon ægyptiacum was contemporaneous with Lepidodendron mosaicum and Sigillaria. Prof. Unger argues, from the presence of this genus, that the sandstone, "hitherto of doubtful rank in the geological series, as no organic remains have been found in it," should be ranked in the Permian, rather than in the Keuper or the Cretaceous formation; but from the palæontological evidence alone he might have argued equally in favour of its Carboniferous age.



The caves in the Mountain Limestone which forms the magnificent gorge of the Elwy, near Cefn, St. Asaph, have furnished from time