138 



stone, and an upper sandstone. On the age of the first of these 

 rocks (much used in statuary by the ancient inhabitants), Mr. New- 

 bold, not having acquired fresh information, simply states that 

 Ehrenberg has referred it to the " Quader Sandstein," whilst 

 the French author, Lefevre, has classed it with the " Keuper," 

 or " Marnes irisees." The next, or the marine limestone, is the 

 Avell-known building stone of the pyramids, which, from the remains 

 it contains, has, I believe, been classed with the calcaire grossier, 

 though the list of fossils given in this memoir points to Cretaceous 

 and Miocene as well as Eocene ages. This limestone is inclined 

 and altered in the proximity of the plutonic rocks. In the upper 

 sandstone, which extends into the Numidian and Libyan deserts, 

 and even to Abyssinia, our author found a few casts of marine shells, 

 but too imperfect to enable him to speculate on the precise age of 

 the tertiary rock. Much interest is attached, however, to this de- 

 posit, in consequence of its being the matrix of the trees which 

 constitute the petrified forest of which this Society formerly received 

 specimens from Lord Prudhoe, and of which my noble friend gave 

 me a very clear verbal description, stating that the trunks of the 

 trees were occasionally in a vertical position, their whole aspect con- 

 veying to him the idea of their being in the place of their growth. 

 Lieut. Newbold describes the stems as chiefly resembling those of a 

 fallen or prostrated forest, the trees being generally directed to 

 the north-west. On clearing away, however, the sand from one of 

 the few stems which are vertical, he found no traces of an ancient 

 soil, like the dirt-bed of our Portland Cycadeae, but, on the contrary, 

 the end of the trunk was imbedded in the conglomerate which is 

 associated with the sandstone*. 



'From the remains in the limestone and sandstone Mr Newbold 

 infers, that those parts of Egypt around the country of petrified 

 trees had twice formed the bed of the ocean, and twice been 

 elevated into dry land, and that the trees in question lived in the 

 period between the two submergences. Posterior to those move- 

 ments of oscillation, which, from the horizontality of the strata, was 

 probably very gradual, the land has undergone additional elevation 

 around the head of the gulf of Suez, and between the Red Sea 

 and the cliffs Avhich skirt its western shores as evidenced by a 

 fringe, in parts about fifty- feet high, of calcareous shelly deposits, 

 charged with the remains of Radiaria, Testacea, and Corals which 

 now inhabit the Red Sea. 



However comparatively recent this elevation may be, Mr. New- 

 bold contends, that the gi'eat dissimilarity of the faunas of the Red 

 Sea and the Mediterranean, renders it probable, that there was 

 an ancient barrier of separation^ and that therefore the isthmus of 

 Suez has not been formed in a recent asra. On this point, how- 

 evei', we have gained still more definite information by the re^ 

 searches of our Curator, Mi-. E. Forbes, and to these I have already 

 alluded. 



* Mr. Robert Brown has pronoimced these trees to be dicotyledonous. 



