, p § N A T Ü R A L $ H If S T O R Y ,
called deads. • Thefe ftreams are o f different- breadthsyt;||MQm defs
fü,n a fathom, oftentimes fcâttered; thongh in .different' qua^titi^,
OVer. the- whole' width o f ihe tmoor^ bottojen, pr. valley, in which
they are found; and when fevers). foebftreanft meet, itheyoften-
times make a very rich floor-dMin, one ftreami|ftoving asritrwer.e
à lMgnefctf© £be-ilietal of-the other.
In the ;teiïement o f Douran,> in the pariftvoflSti Juft, (FenWith)
in the year -if .3 8 , thére jwas a very Angular ftream o f tin difeovered j
thé ore was pulverized, betwixt one foot andsóne foot and a .half
in depth or.»thièknefs, ofvariouS breadth. In the mpory ground,
where it was firft difoevered, it. had a back of- foil and gravel over
it, only two feet high, but, as the ftream advanced farther to the
eaft, it had flail a higher covering* till at daft it had all Douran hill
(which may be about forty feet perpendicular) over it,, the flxeam
continuing ftill its horizontal pofition,: -
That this ftream was collefted from the adjaoenty^rtfftz, .and then
fpread in this equable manner by the force of waters, is extrçamly
prdbable; but how it flioüld become covered? with fuchoa-darge
o f rubble,; clay, and gravel,- as compofestthe hill oft Douran*
is not fo eafy to decide: there are indeed ftrong proofs, in. fom& of
the adjoining cliffs, of large heaps, veryliftle inferieur to .this in-
quantity, which were moil likely laid where we find them by the
waters of the deluge. But whether this remarkable pofition oftare-
naceous tin is owing to the waters of the flood :. {which indeed is a
moft fertile folution of fubterrancous difficulties, but I fear too often
recurred to) may be well queftioned. It fcems to me, that where-r
ever there is an horizontal extended vacancy betwixt the t and
at the bottom of that vacancy an even hard floor, either of ftone,
clay, or gravel, into which the Waters cannot readily fink, and
lodge then depofits in chinks and crevices, there the waters will
fpread their contents horizontally. Suppofe then Ûit Jlrata of
the hill of Douran to be well impregnated with this arenaceous tin,
the waters percolating thro’ the hill would by degrees congregate and
wafh it-forwards till it met with foch an horizontal floor as has been
mentioned, which the tin, not being able by its weight to penetrate,
muff confequently fpread itfelfi upon the furface in breadth
and thicknefs anfwerable to the vacancy which receives it ; and this
is moft likely to be the cafe, and may happen under the higheft
and moft rocky mountains which flood unfhocked by the flood, as
well as here at Douran under a gentle rifing.
There are lèverai jireams of tin in St. Stephen s Branel, St. Ewe,
St. Blazy, and other places, but the moft confiderable ftream of
tin in Cornwall is that of St. Auftel moor, which is a narrow valley
about a furlong wide, (in fome places fomewhat wider) running
near
RfmWimi'Lf'Lf ■ ■ ,i6j-
■ rAufteftfeuthwardto the fea.
Qn’.jea^h’fide,: and’-otatha head-above- St. Auftel are many hills, be-
; twist %hidh there.are little“- valleys« which, lafl difchaf^ their waters,
addwhateverJjdffe,'|hey. r'eeeiW fijpmi'the higher.'grouriefeftinto St..
'Asaftel moor:; whince»ii(jvhappen^!il,at.1the ground ©f this-moor’# all
■ adventitirius for Mlabut three:.fet-honis deep, > theritiodes andiftreairis
from tfeeiihflls orlsSeach fide being here 1 Collected and "ranged" into
floors;-.according «0 their weightf ^nd the foecefllveudates-of their
coming »thither: * dThe uppermofteuceat's confifts -of .thin» layers of
earthy clay," amd'.p&bbly gravel, ■ abbut rive!feefrdefep ; if the1, next
fum is about fix feet deep, more ftony, the-'ftpnes pebblyTofmed;:
with ^ thefe twd CoMerings being/removed;
(hey sfimdfigtea&anmbers i off .tin-ftoncs frofo thesfoignefs nof a 'goofe*
egg, and fern A b e s larger, down to th e fiz e o f the flneftvfand.
The ftnoothed flones; frdfn a
foot diameter downwards to the fmalleft pebble. Erotn.the prefcnt
forfaceof i theiground down to the folid. rock of karn,a:fth eighteen
feet deep at a medium: in the folid. rock there; is nodin. This
ftream-tttfis o f the pureft kind, and gteat part of it, without any
other management than being’wafhed upon tsheripot, brings 13 parts
for twenty at the melting-lhoufe*. In one of the workings .herd were.’
lately found;l about eight feet under the fiirfiice, two flabs, or final!
Blocks o f ' melted tin, 1of about? twenty-eight pounds weight each, -
of a fhape very different from that which for many years, .has obtained
in Cornwall;. andas they have no ftamp?orithem,tprobably
Is dliis^the time-when the Jews had eiigrofied the tin. maaufofture
in ihe time of Ring John;! They have femieireular handles oriibops
to them, as if to fling and carry them more conveniendyofr horfo-
back: they are much corroded by the fharp waters in which they
have layn, a kind o f ruft or fcurf-like incruftation inclofing the tin.
Probably there were fome Jewifh melting-houfes near the place,
and when thefe houfes were plundered and deftroyed, fome soft the
blocks remained in the rubbifh, and by the" floods; which this valley
is fb fttbjetft to, wafhedodown wards, and covered where they? were
found. Their fhape and dimenfions may be feen Plate RXi lEig. xtx.
A is the upper-part, B the under-part of this ancient block ©frtimf!
In the ftream-works in St. Stephen’s Branel,. they alfo find; now
and then fome final! lumps of melted tin, two finches fquarfrand
under I what I havetfeen of this' kinef cuts with difficulty;’' ■ flridsfriore
harfh and gritty than the common melted tin, .owing to! this; .per?
haps, that the ancient melters had not then; difeovered how to flux
* Upon delivering twenty pounds of this tin- ■ to deliver to the owner’s Order thirteen pounds of
«re at the melting-houfe, the mclter wilVcontniiSL'jfjmelted tin at the coynage. j -
their;