MI NER A L OG Y. 
^9 
nlou-ntaiBS. Tlie chert is likewife found plentifully in 
the neighbourhood of fcaly limeilone, as flint is in the flrata 
of chalk. What connexion there may be-between thefe bo- 
dies, perhaps time will difcover. 
- But flints and agatds being always found in loofe and 
Angle irn-gular nodules, and never in rocks, as die cherc, is 
a circurailance very infuffi.cient to eftablifli a difference be- 
tween them ; for there is agate near Conftantinople rdiining 
vein-like acrofs the rock with its country, of the fame hard- 
nefs, and as fine and tranfparent as thofc other agates, which 
are found in round nodules at Dfc*ux Fonts. We muft there- 
fore content ourfelves with this remark concerning flints, That 
they feem to be the only kind of Hone hitherto known, of 
which a very large quantity has been formed in the fhape of 
loofe or feparate. nodules, each furrounded with its proper 
cruft ; and that the matter which conftituces this cruft, has 
been feparated from the reft of the fubftance in like manner 
as fan diver, or glafs gall, feparates from, and fwims upon 
glafs during its vitrification ; tho’ fometimes the formation of 
this cruft may have been prevented, by the too fudden harden- 
ing" of the matter itfelf : i fliali therefore take the liberty 
to call this matter of the cruft, which ibmeiiines' is an in- 
durated terre verte, by the name of jigate-galL' 
Other fpecies of ftones, which are found in loofe pieces, 
or nodules, except ores, and fonie forts of ftalaiftites, fhew 
evidently by their cracks, angles, and irregular figures, that 
they_ have been torn from rocks, lolied about, and rubbed 
lagainft one another in, torrents, or by fome other violent 
motions of water. That flints have originally been in afoft 
ftate, as i have mentioned, is eafy to be feen in the Egyptian 
pebbles, . which have imprefiions of fmall ftones, fand, and, 
fometimes perhaps grafs, which however have not had any 
ingrefs into the very flint, but feem only to have forced the 
abovementioned agate gall or cruft out of the way f. 
SECT. I.XIV. 
G. Jafper, Jafpls, 
Ail the opaque flints are called by this 
name, whole texture refembles dry clay, and 
which have no other knov/n quality, whereby 
ft The erroneous noi ion of the once foft ftate of ftones, fee difeuffed 
in my Firft Letrure on Fcftii,-. D. C. 
F 3 they 
