E A 
Inflation between themfelves, vaft cavities were formed 
under that cruft. The firft great event depending pn that 
caufe, fixes the end of this period: this was the fink¬ 
ing at once of a great part of the cruft, and the accumu¬ 
lation of the liquid over that funken part. Thus dry 
lands of various fizes were produced, on which vegetation 
began. 
Fourth Period. —It is only from that fil'd revolution 
in the bottom of the liquid, that we may feparately 
confider our continents as being then the bed of the fea. 
That great alteration in the combinations of caufes, both 
in tire now broken bottom of the liquid, and in the li¬ 
quid itfelf, together with an increal'e.of light, prepared 
new events. The bed of the fea, though formed of funken 
frata, was not yet fo broken, nor thole frata fo diflo- 
cated, as they became afterward, from a continued re¬ 
treat of the loofe fubftances under them: but they were, 
in many parts, covered with fragments of their fubftances, 
which, mixed afterward with various' powders, either 
gathered or precipitated, were confolidated in diftinCt 
Jlrata. To this period I aferibe the beginning of the phof- 
phoric decompofition by which our fun emits light, and 
from which.smr globe then began to receive a conftant 
fupply of that fubftance. 
Fifth Period.— Many great events belong to this 
part of the exiftence of our globe ; the fir ft of which is, that 
the fea began to be peopled with animals. They had not 
exifted before ; for we find none of their relids in the 
former frata, and their firfl appearance is in fome frata 
of fckifus, which were (fill forming: but a little after, 
probably by a new and conftant fupply of light, the li¬ 
quid was difpofed to the diftinCt: precipitation of calcareous 
fubftances, and all the former precipitations were flopped. 
Intmenfe calcareous frata, of various forts, were then 
formed all over the bottom of the liquid, by which 
the primary frata were covered. In fome of thefe fecon- 
daryfrata, either in the fame fets, or in different parts 
of the fea, a great quantity of relids of fa animals were 
buried ; but in many other frata of the fame kind, even 
in the fame fets, there were few br none depofited. The 
fame difference, refpecting the exuviae of fa animals , hap¬ 
pened in fome of the io\\ow\ng frata : fome have none ; 
and fome-, in which no calcareous fubftance was depofited, 
excepting thofe exuvia themfelves, contain a prodigious 
quantity of them. Among the fa animals, whofe relids 
are depofited in thofe calcareous frata, were many fpecies 
which difappeared when that kind of precipitation was 
at an end. During that diftinct precipitation a new fort 
of revolution began in the bottom of the fa, by volcanic 
eruptions:, and many volcanic cones were furrounded, as 
lavas covered by calcareous frata. Towards the end of 
this period, other great revolutions of the firfl clafs 
took place, by partial falls of the bottom of the fea, in 
its whole extent, owing to the continued retreat of the 
loofe materials under the folid frata. In thofe falls, 
fome of the deeply broken frata being turned up,, in 
falling more on one fide than on the other, and fome 
parts of them being prevented from falling, by the re- 
ti fiance of concreted fubftances under them, vaft ridges of 
different forms were produced on the furface of our 
future continents. To this only it is owing, that tha 
lowermoft frata of our land happen to be under our 
infpedtion : we fee them dearly turned up in the center 
of our great ridges of mountains ; and, diredted by that 
immediate information, we difeern them in fmaller ridges, 
and in their fragments fcattered over many parts ,of the 
uppermolt frata. In thofe revolutions, alfo, many 
ijlands which had remained up in the third period, and 
on which vegetation had produced great accumulations of 
peat, funk for the firfl time, and were afterward covered 
with other kinds of frata. At that time, however, the 
bed of the fea was the only theatre of revolutions ; a 
great mafs of land remained, which had not yielded to 
the retreat of the loofe fubftances under it. 
Vob. VI. No. 341. 
R T H. . 181 
Sixth Period. — Another great alteration happened 
now in the fea. Not only the precipitation which had 
produced Jolid calcareous frata ended in mod parts of the 
liquid ; but this was rendered capable, perhaps by the 
volcanic eruptions continuing with violence, of di/Jolving 
many calcareous frata of the chalk kind, of which remains 
only the finty gravel found in fo many parts of our con¬ 
tinents. The origin of that gravel is. manifefted by the 
fame marine bodies which exift in our chalk frata, and 
fometimes by chalk itfelf being found in its maft'es. 
Many forts of frata belong to this Feriod ; the firfl of 
which proceeded from a precipitation of [and, which, in 
many parts of the fea, was confolidated in frata over thofe 
of lime-fonc. After this, and fome other precipitations, 
new revolutions happened in the bed of the fa, by which 
the J'and and calcareous (trata were broken and diflocated ; 
as were the particular fets which contain our coals. As 
all thefe revolutions had for their common caufe the 
finking of new parts of the bottom of the fa, the level 
of the fa itfelf funk alfo more and more; and then the 
upper parts of the high ridges, which had remained be¬ 
tween'fallen parts, appeared as funds over that level, 
and began to be covered with vegetation. In the latter 
part of this period, many new forts of frata were formed 
over the ruins of the former: thefe are ftrata of clay, 
marie, J'and with gravel, and ftrata of various forts of pure 
find. The molt parts of thofe frata were fuch as could 
not confolidate, except partially. The fa animals, which, 
notwithftanding the above revolutions, continued to pro¬ 
pagate in many parts of the fa, became nearer and nearer 
the fpecies which inhabit ttie prefent Jiea, and their relids 
were depofited in great abundance in many of the new 
frata: fome are not very ancient, for we find them ftiil 
with their native colours, which have vanifhed in the more 
ancient ones : however, among the more recent, there 
are fome whofe fpecies now exift only in very remote 
parts of our fea. Thefe remains of the lateft inhabitants 
of the ancient /ra are often found mixed with remains of 
animals and vegetables proceeding from a continent, which 
then Hill exilted: or rather, this faCt proves rite exift¬ 
ence of that continent, and that it was then peopled with 
animals. We are now Come near another revolution, of 
which I am not to (peak in this place, having here only 
to trace the formation of our continents under the fea. The 
revolutions which produced their charaCteriftic form were 
moftly at an end, by the loofe fubftances under them be¬ 
ing fettled ; confequently tiiey were nearly the fame as 
we fee them now. The continent, on which the animals 
lived, whofe exuvitz were carried to fome parts of the Jea, 
ftili exifted ; being, by its folid*compofition, fupported 
over the cavities formed by the retreat of the loofe fub¬ 
ftances under it: however, in that ftate, it was expofed 
to the fame fort of revolution which had happened over 
the reft of the globe. 
I confine myfelf, fir, within thofe narrow limits, in re- 
fpeCt of the operations and revolutions that happened 
on our globe, prior to the. retreat of the Jea from our con¬ 
tinents : but, in that mere fketcli, I have pointed out a 
fucceffion of caufes, whofe' churaCteriftic effeCts are dif- 
tinCtly marked on the liirface of thofe continents: and this 
I think fufficient to flievv, that the theory of precipitation 
is the only one that can bear to be examined compara¬ 
tively with t he prefent ftate of our frata. The only 
argument which you have oppofed to that theory is, that 
Jubfances precipitated in a liquid, ought to be ftiilfoluble by that 
liquid: but a moment’s reflection would have made you dif- 
cover, that, on the contrary, no fubftance can b e precipitated 
in a liquid, while that liquid (till retains the faculty oidijjolv- 
ing it; and, in general, that the very modifications which 
produce the precipitation of fubftances in a liquid are the 
caufe of its incapacity of dilfolving them again. As for 
the admiflion of an original liquid, fuch,as I have Ex¬ 
plained it, if it gives a clear, though not a precife, idea, 
of the great phenomena obferved on the furface of our 
3 A globe* 
