C u ] 
THE laws of generation perfiiade us to cornmence our claffification 
in earths, but the laws of fyllem are repugnant. 
For earths by general confent, conftitute a natural order, and 
flioulil not therefore be divided into different dalTes. 
Congeneric fpecies, fhotild like wife be feparatcd from others of 
a like genus: for foine clays refill the gre^tcft degrees of heat, 
others are calcareous. 
Ochres alfq fhould precede Metals, before the idea of iVJetals is 
given, wbofe progeny they neyerthelefs are; yet fome Ochres 
mult be referred to Copper, foinc to Iron, Bifijiuth, &c. 
Some fpecies of earths are primitive and (hould precede rocks; 
others are derivative and fhpuid be plapcd after them. 
If Foffils be divided among Stones or Minerals, then Tophs 
and Stalaaitcs would he feparated from their natural genus and 
dillributed aipong different ones. 
Many petrifa£tiqns would be placed among calcareous rocks, 
fome among combultih'cs, others arttong Pyrites, Copper, bi- 
tumen, &c. 
CRYSTALS I would have placed among the Salts; but to prevent 
a mere difpute about words, he that ihtpks fit may ealily fubllitmc 
the term C'ryftal in the room of Salt, ror is it not the fame thing 
to fay that baits have determined their figure under the generation 
of Salts, or that they are the conif itutive clem.ents of Salts ? 
