A SYSTEM OF 
2-42:- 
APPENDIX. 
SECT. CCLIX. 
I Have already in the Preface mentioned the rea^ 
fons why the Saxa and Foffils commonly calleci 
Petrefadions, cannot be ranked in a mineral 
fyftem : And I am almoft perfuadedj that the fame 
reafon which has prevailed on me, will likewife 
after mature confideration be approved by others. 
Mean while,, fince thefe bodies, efpecially the lat~ 
ter, occupy lb confiderable a place in moft mine- 
ral colledions,, and the former mull necelTarily be 
taken notice of by the miners in the obfervations 
they make in the fiibterranean geography, I 
would not entirely omit them here, but have 
tried to put them in fuch an order as may anfwer 
that purpofe, for which, miners and mineralifts pa|i 
any regard to them. 
SECT. CCLX. 
The FIRST OR D E R. 
SAXA. P e:, T R iE. 
I divide thefe into two kind:s,- 
Compound Saxa, Saxa compojita^ 
Are fuch ilones whofe 'particles, confifting, 
of different fubftances, are fo exadiy fitted 
and joined together, that no empty fpace, or 
even cement, can be perceived: between them 
which feems to indicate, that fome,, if not alh 
ok 
