to be poliihed, is altogether penetrated by veins o f calcareous
cryftallized fpar, which furround fmall bits of flint, full o f mi--
nute marine bodiis, o f the frumentary kind. This piece is well
calculated to puzzle any one who flattered himfelf that he had a
clear idea o f the formation of flints*. Henckel, in his Pyritohgia,
after having faid much on .the fubjedt, confafies, that it was unintelligible.*
Concerning a Mine o f P i s s a s p h A l t i t m .
The foffil curiofity o f Bua, which, in my opinion, merits
greater attention than all the reft, is the mine o f Pijfafpbaltum.
I venture to call it a mine, however improper the term may appear,
that ! may .not be obliged to call it a fpring, which would
feem ftill a more ftrange denomination. The ifland o f Bua is
divided into two.promontories., between the weft and north, one
o f which faces the ifland of.Salta, and the other is extended op-
polite to Trau. Crofling over the top of this laft, which is not
half a mile broad, and defcending in a right line towards the
fea, one is condufted to a hole well known to the inhabitants.
This hole extends not much above twelve feet, and from its bottom,
above twenty-five feet perpendicular, arife the marble ftra-
ta which fuftain the irregular maflfes that furround the top o f
the mountain.
'th e
* In the colleQion o f the noble Venetian Giacomo Morofini, there is,
among many other valuable foffil curiofities, a fmall table of Jafper, taken
from the hills o f Recoaro, near the mineral fpring, whereof the Tubftance of the
Hone, and the ihells of the Terebratula and Gripbites entangled in it are filiceous 1
and the internal of thefe marine bodies is full of a white and very bright calcareous
cryftalliaation.