[ 7^ ] 



fufpended in an aqueous fluid. As to the compad limeftones and 

 marbles, in which the teftaceous cxuvite of marine animals 

 abound, it is evident that if thefe ftones were ever melted, thofe 

 would, with them, run into one common mafs, as we have 

 already faid. Other ftones of this clafs are more impure, 

 and mixed with argill and filex in fuch proportion as to be 

 vitrihable in fuch heats as art can eafily produce, yet we never 

 find them in that flate ; a circumftance which clearly excludes 

 all fufpicion of their ever having been expofed to them. 



In the muriatic clafs, we fee fteatites and pott-ftone, which 

 in their a<5lual flate have a foft foapy feel, but harden when 

 heated, vitrify in a ftronger heat, and acquire a texture and 

 hardnefs quite different from thofe they before pofleiTed. 

 Steatites often contain 1 6 per cent, of air and water ; thefe cha- 

 radters depofe in favour of an aqueous origin : but ferpentines, 

 of which whole mountains often confift, demand this origin 

 more loudly ; for they are infufible in all but the moft extreme 

 degrees of heat, in which they vitrify and acquire the polifli, 

 texture, and luftre of glafs. 



In the argillaceous clafs, we meet with argillaceous flates, 

 hornblends, and trapps or bafalts ; all of which are in a mode- 

 rate heat converted into flags, whofe appearances totally difi'er 

 from that which thefe fiones prefent in their natural flate ; and 

 hence they evidently difclaim an igneous origin. Mica has 

 been clearly proved to originate in water by Mr. Nauovarke, 

 I Chy. An. 1786. 



In 



