PREFACE. xv 



pi&ure, drawn and coloured after Nature; 

 and prove of nearly the fame advantage to 

 miners and philofophers, as well-delineated 

 anatomical tables are of to furgeons and 

 phyficians. 



I (hall point out where this fyftem was 

 deficient, and by that means flate where it 

 remains fo (till. 



The problem to be refolded was, in ge- 

 neral, laid down upon too narrow princi-* 

 pies. It was only to explain the origin of 

 the inequalities, and of the fea-mells con- 

 tained in their various parallel ftrata. This, 

 indeed, is but part of the queftion. The 

 higher metallic and Jimple mountains ; their 

 fiflures and veins ; their rocks, which never 

 contain any adventitious organic body ; their 

 different relative fituation, in refpedl to them- 

 felves, and to the many marine or other 

 beds which are incumbent on them ; have 

 not been properly attended to : till very 

 lately, we were entirely deftitute of fcien- 

 tific and intelligible defcriptions of moun- 

 tains and mines, and the refpective natural 

 iituation of their beds and rocks. This de- 

 ficiency has been, of late, perceived and fup- 

 6 plied 



