8S8 Mr Nicol on the Structure of Fossil fVoods. 



seen in any degree warrant such an opinion. The wood breccia 

 is from a bed at the edge of a large chasm, which traverses for 

 a considerable distance sandstone strata, to the south-east of the 

 ruined town and castle of Kalat Adde, and about a league and 

 a half from Ipsambul. The specimens of Egyptian fossil wood 

 are from Gebel Ataka, and Wadi el Tiheh, three leagues south- 

 east of Cairo ; and in regard to the fossil trees of that district, 

 Mr St John, in his lately published Travels, remarks, that " se- 

 veral of the trunks measured three feet in diameter, and from 

 forty to fifty-two feet in length," and that the tops of the hills, 

 the beds of the torrents, the hollows, the glens, and ravines, are 

 profusely covered with these petrifactions." 



III. Fossil Coniferous Woods found in the Karoo Ground^ wpvoards 

 of 400 miles North-east from the Cape of Good Hope, by Mr 



James Scott of Greenock. 



The fossil woods from southern Africa are of the siliceous 

 kind, and, from a peculiar glaze on their surfaces, would appear 

 to have been long exposed to the action of the weather, although 

 they shew no signs of having been worn by attrition. The ex- 

 ternal appearance of these fossils clearly indicates a vegetable 

 origin, and from the natural polish of the ends of each, an ex- 

 perienced eye, aided by a common pocket lens, would find no 

 difficulty in determining them to be coniferae. A thin transverse 

 section shews in both most distinctly the coniferous reticulation. 

 In one of the specimens, the rows of vessels are very much com- 

 pressed in the dinction of the radial partitions, and the annual 

 layers, which are well defined, present an unusual disparity in 

 their relative breadths. A longitudinal section of one of the spe- 

 cimens parallel to the radial partitions, displays, though faintly, 

 discs similar to those in the recent araucarias. A transverse sec- 

 tion of another specimen, in some places shews the coniferous 

 reticulation very distinctly, but by far the greatest jDart of it is 

 twisted and contorted in such a manner as nearly to obliterate 

 the original structure. 



These specimens were found by Mr Scott in one of the Karoo 

 Plains, north-east from the Cape of Good Hope. He informs 

 Professor Jameson, that the Karoo was covered with this fossil 

 wood for upwards of twenty miles. 



