90 DOMAIN I. STDEROUS. 



nesite, or magnesian earth mingled with iron*. 

 The agates afford valuable materials for manu- 

 facturers ; and the rock abounds in many coun- 

 tries, as at Oberstein on the Rhine, Kinnoul and 

 other places on the river Tay, in Scotland, 

 whence the English lapidaries have called the 

 latter agates Scotch pebbles f. In the north of 

 Italy the same rock presents chalcedonies, which 

 are sometimes enhydrous, or contain a drop of 

 water. In the Faroe isles the chalcedony com- 

 , monly assumes the stalactitic form ; and, as 

 Landt observes J, it has been found modelling 

 itself on straw or moss, whence it clearly appears 

 to have been deposited by water; either heated 

 by its own caloric (for if water contained no 

 principle of heat it would become ice), or by 

 subterraneous fires, as the fountain of Geyser in 

 Iceland deposits silicious concretions. 

 Formations. Werner considers Amygdalite as of two form- 

 ations ; the Transitive, the base of which he calls 

 wacken, an argillaceous rock, sometimes inclin- 

 ing to basaltin, which it generally accompanies, 

 and sometimes to iron-stone, a mixture of iron 



* This may also be called a lole, a shorter word than lithomarga, 

 and expressive of the same substance, as appears from the analyses. 



f This name seems also a distinction from the English pebbles 

 in pudding-stone, &c. some of which are as beautiful as agates. 

 P. 146. 



