DOMAIN I. SIDEROUS. 



the ancients, often present marks of crystal- 

 lisation, being sideritic rocks or primitive traps, 

 they shall be considered /under that division. 

 Wad, in his account of the Egyptian minerals in 

 the Borgian Museum*, observes, that the ba- 

 Ancient basalt, saltic monuments of the ancients are referable 

 to two classes; 1. The primitive, consisting of 

 black hornblende, or siderite, which is some-* 

 times so mingled with veins of felspar, and often 

 with quartz and felspar, partly rude partly crys- 

 tallised, that it is in some examples difficult to 

 determine whether they should be placed among 

 the basalts, or syenites, of Werner. 2. This 

 class appears of more recent formation, and in 

 all respects agrees with the basalt of Werner, 

 except that it be more hard, owing to the inter- 

 spersion of minute particles of quartz, being 

 very similar to the stone with which the ancient 

 Roman ways were paved, and which is by some 

 called lava. Some of the ancient basalts there- 

 fore cannot be distinguished from siderites, as 

 the ancients were not conversant in the minute 

 discriminations of modern science : and some 

 monuments which they would have called ba- 

 salts, a modern mineralogist would rank among 

 the black granites. But as the ancients cannot 

 be our guides in mineralogy, a science to them 



* Fossilia 5igyptiaca Musei Borgiani. Felitris, 1794, 4to. p. 7 



