58 DOMAIN I. SIDEROUS. 



" 6. But without mentioning basalts, which 

 have so many volcanic characters, a great ana- 

 logy is found between secondary mandelstein 

 and porous lavas; between the clay of trap 

 mountains and the products of muddy eruptions; 

 between basaltic tufa and volcanic tufa; and 

 almost all minerals which are found scattered 

 in volcanic masses, are found in trap moun- 

 tains, &c. 



" 7. The position of secondary traps, which 

 lie over all secondary rocks, while the hardness, 

 compactness, and other characters of many 

 among them, such as grunstein, basalt, and 

 others, are so different from those of the se- 

 condary rocks on which they lie. That kind 

 of dry ness to the feel which they present, and 

 which is characteristic of volcanic productions 

 in general, .all these approximations will not 

 permit us to acknowledge that basalts have had 

 the same origin as all secondary rocks. 



" 8. It has been objected that in basaltic 

 countries basalt is found on almost all the sum- 

 mits, and that such would not be the case if 

 basalts were lavas: this might be true if these 

 lavas proceeded from a recent deposition ; but 

 on the contrary this deposit seems very ancient, 

 and has undergone many changes. M. Reuss 

 himself observed in Bohemia, that the basaltic 



