i 5 8 '±Êpà A T U R A L H I- S T O R Y
in its original perpendicular pofition, and M F flfatum où
any precarious foundation to give way and defcend to R L F, then,
will the Iodé N F defcend alfo, and become O E F . - A piece of
the fame ftratum, R L , is afterwards rmfooted, and becomes S IK ,
then will the lode, O E, fall in -proportion, and become P C D.
Another fubfidence happens from like concurrent caufes, and S I
fhall become G H ; then fliall that portion of the lode, P C, fall
into the pofition of A B, and, in proportion to the -times and
falls of the Under Jirata, fliall the lodes defcend either in. whole or
in part. It may lie laid, that if thefe fubfidences were the caufes of
the above-mentioned fradtures, then the interftices of fuefr broken
lodes would be filled by earth, clayf gravel, arid fudh lóofe materials,
as the difordered Jirata could nol but throw into the opened crevices
; this is very true, and the matter of fadf confirms the fpecu-
lation ; for between B and G, D and E, (ibid.) a fhelvihg-foft.'congeries
of rubble, clay, fand, Or the like, (by.; the Cornifti balled a
Flôokan) is interpofed: it is of a different fiibftance ffom the
lode and wall of the fiflbre, and by the vulgar is"1 thought -the jchhfo
o f the lode’s being ftarted ; but is indeed the effedt, and -nothing
more than the depofite of the adjoining grounds after the fradture
of the lode had been made,
sect. xi. As we have endeavoured to fhew that the fubfidences- of the
CaufeofthcJirata were the caufe of the inclination and fradture o f lodes, it can-
Aeftrata. not be improper to hint at the date and jcaufê df thefe fobfitfetfees.
It has been obferved before, (page 80) that, at the firft induration
of bodies, it was impoffible, but that the fiirface of our globe
fhould be higher in fome parts, and lower in the reft ; that the
earth, porous and cavernous as it muft be by the intermixture of
fubftances apt to give way, ferment, and explode, muft fink deep
in fome places, and lefs, or not at all, in other places. Now, as
we owe the mountainous and hilly parts of our globe to the folids
which ftood firm and prominent, fo to thefe depreflions óf the more
lax and cavernous parts we owe the bed of the ocean, and the fubfidence
of vallies ; but thefe depreflions, fo neceflary, (the lefler to
conduct the rivers, and the greater to contain and form the fea)
could not but influence more or lefs all the adjoining flr'ata, and
the Jirata all their fifliires and lodes ; hence fo manifeft a relation
in many parts to thefe firft and principal depreflions.
Secondly, When the fea was formed, its fearching fluctuating
waters wafiied and exhaufted the loofer fubftances from betwixt the
J ir a ta and time occasioned many fubfidences of the higher upon
the lower Jirata, 'which fubfidences muft have been in fize and
tendency according to the Shape and dimenfions of the vacancies
from
O F ;C O R N W A .X L , i 5g
from which fiich loofe fubftances were educted, and not to their
Situation with regard to, the fea. To thefe fecondaiy fubfidences
we may afcribe irregular and contrary inclinations df our lodes.
Thirdly, When it was determined that an univerfal deluge fhould
deftroy all terreftrial animals, excepting only a fmall number pre-
ferved in order to reftore the feveral fpecies : to produce this deluge,
the fea moft. probably was the chief infiniment ; its bottom
inflated, and raifed fo as to throw its waters over the higheft mountains,
covering them as a garment. When the Divine Juftice was
fatisfied, the bottom of the fea returned nearly ,to:its former level,
yet not fo exactly -, but that it left feme parts above, the fea (now
iflands or hills) which were before part of the ocean’s bed ; the
Jirata of thofe parts were therefore greatly disjointed, fome inclining
one way, fome another, fome quite reverfed. To ithis dreadful
ÿhtaftrophe i r ê fW tó ‘ attribute many irregularities -of thé fttaiày
which have no correfpondence or the leaft relation to the primary
tfubfidenles. ,
But whatever was the inftrumental caufe o f the deluge, that there
has been a deluge is the united voice of tradition, of Scripture, and
•°f nature; and from fact it appears, that this deluge difiblved all
«clays, earths, faits, and the fofter ftones, and muft have occafioned
Igreàt' ebullitions, and explofions. among the pyrites, felts, and fiit-
•phurs, whenever its waters pierced} and hence happened very con-
fiderable fubfidences in the protuberant parts of our globe, where
the fea never before reached fo as to afiedt the Jirata.,
; Laftly, a few fubfidences may have happened fince the deluge,
from the fame exhaufting diflolvent powers of water, inundations,
or by the. force of earthquakes, but none could.-happen either firft
or laft, from whatever caufe, or at whatever time, without altering
the fituation of all folids within their reach, in proportion to the
force with which they acted upon the adjacent grounds.
C H A P . XV.
O f Metals found in Cornwall ; and firfl o f Tan.
HA V IN G examined the fifliires and the lodes, and their feveral
properties moft worthy of notice, we muft proceed in the
next place to the metals which our Comifh lodes contain.
Of metals Tin is the lighteft, and therefore fhould be the firft in
•pur feale, if there were no other reafon than the ufiial method of
ranging metals according to their fpecific gravity} but tin would
ptherwife deferve the firft notice here, becaufe it is in a manner the
peculiar
• See page 78.