INTRODUCTION. 



XXXV 



6 Second Floetz Limestone. 



7 Third Floetz Sandstone. 



8 Rock Salt Formation. 



9 Chalk Formation. 



10 Floetz Trap Formation. 



CLASS IV. 



1 Peat. 



2 Sand and Gravel. 



3 Loam. 



4 Bog Iron Ore. 



11 Independent Coal Form- 



ation. 



12 Newest Floetz Trap 



Formation. 



diluvial Rocks. 



5 Nagelfluh. 



6 Calc-tuff. 



7 Calc-sinter. 



1 Burnt Clay. 



2 Porcelain Jasper. 



3 Earth- Slag. 



CLASS V. Volcanic Rocks. 

 Pseudo Volcanic Rocks. 



4 Columnar Clay Ironstone. 



5 Polier, or Polishing Slate. 



True Volcanic Rocks. 



1 Ejected Stones and Ashes. 



2 Different Kinds of Lava. 



3 The Matter of muddy 

 Eruptions. 



4. Admission of Iron as an Earth. 



The admission of iron, not as a metal, but as an earth, 

 may occasion some hesitation ; and a few preliminary obser- 

 vations become necessary. Many eminent mineralogists and Admitted by 

 geologists have led the way to this improvement, though 

 they have not formally introduced it into a system. It may 

 be preferable to adduce their testimonies in chronological 

 order. 



Linneus has thus expressed himself, in his brief and em- Linneus. 

 phatic language : " I have sedulously enquired, during my 

 various travels, into the production of stones, and have 

 learned that it is effected by precipitation and crystallisation ; 

 and that earths are deposited, while quartz, felspar, and mica 

 rise up. The female earths are impregnated by the male 



