( XV ) 



doms, as are not ufually found in their natural 

 ftate, and in this refpect they belong properly 

 to the ftudies of the Botanifts and Zoologifts, 

 For a Mineralift is fatisfied with a fingle fpeci- 

 men of each different fubftance that has taken 

 the fhape of a vegetable or animal body, and 

 this only to illuftrate the hiftory of their ge- 

 neration ; he leaves it to others to decide if 

 corals are vegetables, or the habitations of 

 worms \ and thus receives them very uncon- 

 cernedly, after they have been mouldered to a 

 chalk, changed into a fpar, or into any other 

 ftony matter. Neverthelefs, I have in the 

 Appendix propofed a method for ranging the 

 Saxa and Petrefacla in regard to the economical 

 ufes that may be expected from them. 



Slate fignifies or denotes the form alone, and 

 not its kind or qualities ; however, it regards 

 only its fituation in the rock, and not the tex- 

 ture of its particles ; which latter I have always 

 endeavoured to take notice of, fince fome dif- 

 ference in the effects frequently depends on it. 

 And, as nothing is great or fmall but by com- 

 parifon, it is difficult ftridtly to determine in 

 what degree of thicknefs or thinnefs a ftone 

 begins to defervc the name of a flate. Never- 

 thelefs, I would have prevailed on myfelf to 

 adopt this general name, if the breaking in 

 thin plates had been the property only of 

 any particular kind of ftone, but it is by no 

 means the cafe; becaufe there is found in the 

 province of Jemteland, in Sweden, a pure 

 quartz, limeftone, (both folic! and fcaly) indu-r 



rafe4 



