12 MINERA LOGICAL 
down from the mountains;, and formed 
beds in the valleys. 
This ftream-tin is found of different 
lize, colour, and figure, but moft com¬ 
monly rounded by water, and very like 
the common pebble, excepting in its very 
confiderable weight. 
The ftream - tin collected at Ladock 
principally confifts of fuch round, oval, 
fomewhat fmooth pieces, in general from 
the fize of a bean to that of a pea, and 
lefs, whofe polifhed furfaces fhew great 
variety of reddifh grey, light brown, and 
dark yellow colours. 
A fimilar ftream-tin from Penfagillis 
is remarkable on account of the native 
gold, which now and then is met with in 
it; and found, though very rare, in pieces 
of the value of two or three pounds fter- 
ling. In my collection from this place is 
a grain of native gold, of the fize of a 
flattened pea, with a cryftallized furface. 
Probably in ancient times there were in 
thefe hills veins of gold, which have 
been broken down by violent inundations. 
Stream- 
