E A 
accumulated againf fuch Shores: and when thefe Jediments 
do not come to bind the light J'and of the fea, belides its 
accumulation againft the (bore, it is railed by the winds 
at fome diftance, and forms thereby fuccefljve rows of 
Jand-hills, fometimes very high. Thefe are natural and 
certain effects of the waves upon every Jhore, either origi¬ 
nally /helving,, or reduced to that form by the operations 
I (hall deferibe hereafter: and its maximum takes place, 
when there is fuch a declivity, as to produce an equilibrium 
between a greater impulfe of the advancing waves, but 
along an afeending plane, and the fmaller impulfe of the 
retreating waves, but on a descending plane. When that 
equilibrium is produced, nothing more .can happen, nor in 
fact happens, upon any coaf, but fm'all alternatives of 
par i d iiureafes and decreafes, according to variable cir¬ 
cumstances. 
I come now to the remarkable reftilt of your enquiries 
on the defeuplion of our continents. “ Every revolution of 
the globe, you fay, p. 29S, wears away fome.part of fome rock 
upon fome coaf ; but the quantity of that decreafe, in mca. 
fired time, is not a mcafurable thing . . . the age of man 
does no more in that Cftimate, than a Tingle year .... 
But man is not confined to what he fees ; he has the ex¬ 
perience of former men. Let us then go to the Romans 
and the Greeks in Search of a mcafure of our coafs, which 
may be compared with the prefent (late of things.” Af¬ 
ter that enquiry, you acknowledge, p. 301, “ that this 
decreafe of the coafs in general has not been obferved ; and 
that it is as generally thought that the land is gaining upon 
the fea, as that the fea is gaining upon the land.” However, 
you conclude in this manner : “ To Sum up the argu¬ 
ment, we are certain that all the coafs of.the prefent conti¬ 
nents are wafed by the Jea, and conftantly wearing away 
upon the whole.” This is a very pofitive decifion again!! 
acknowledged fadfs; and it would require very Itrong 
arguments to Support it: however, you adduce none but 
thofe which I have quoted above, to w hich I (hall an¬ 
swer, in continuing to deferibe the operations of the Jea 
Upon the coafs. 
When our continents firft appeared above the level of 
they«z, their coafs were not all of that /helving form on 
which I have proved that the fea lias no deftnfotive 
power? fome were abrupt, and there began an apparent 
definition. The cliffs, compoled of loofie materials, fell 
down apace, the currents drove along the Shore a great 
part of the light materials, but the gravel, and the coarfe 
Jand, funk and remained under the cliffs. In that manner 
have been formed thofe frauds and beaches which we find 
now along every Sleep coaf, and over many of which we 
fee already the inoffenfive Surge of the Jea, dying away, 
in rolling fome gravel backwards and forwards, or Smooth¬ 
ing the/anrf. This is the attrition cf one hard body upon 
another, which, p. 296, you fuppofe to give occafon to the 
inf ability of our continents. But the duf produced thereby 
does not vanifii: in falling between the large materials, 
it concurs with the Jand of the cliffs to give them f ability ; 
for, in that manner, a folid bottom.is produced, that riles 
by degrees, and on which the new gravel only continues 
to be rolled by the waves. 
I have had many opportunities of Studying thofe f rands 
and beaches along various fieep coafis : very few of thefe 
are ft ill attacked by the fea itfelf; they are moftly im¬ 
paired by the land-water filtrating in them, which, in 
loofening the materials, brings down Sometimes large 
rnaffes of them within the reach of the waves. Then 
the agitation of the fea carries away again the minute ma¬ 
terials, but leaves the large ones upon the beach, which 
thereby rifes more and more. I have feen thofe grow¬ 
ing outworks of our land in all their degrees. In fome 
parts, where the quantity of large materials is but Small 
in the land, the fea (bill over-runs the beach every tide : 
in other parts, it only rifes over it in Spring-tides With 
high winds; and in many parts, the cliffs are already re¬ 
tired at a diftance, and reduced in a loft Slope covered 
with vegetation. There ends all deftruitive power of the 
fea for it reaches no more fuch coafs , being Separated 
Vol. VI. No. 341. 
r t it. m 
from them by the f rand. Thofe coafs, then, are in tire 
cafe of continental grounds, which are preferved when 
covered by vegetation ; and the fraud itfelf has acquired 
that degree of declivity, which renders it unimpairable by 
the waves. Now, fir, by the obfervahle gradation of thofe 
effedls of known caufes, we are irrefiftibly led to conclude, 
that, in time, our land will, in the fame manner, be every 
where absolutely inattackable by the fea. 
In your Speculative fyftem of decay of our continents, 
you had not considered any of thofe objefts; for you 
Speak only of the wearing away offome part of fome rock upon, 
fome coaf, by every revolution of the globe. In this refpett, 
not having found any certain diminution of any known 
rocks, from the times of the Greeks and Romans, you 
think, with reafon, that this proceeds only from tire want 
of an exnrfl measurement of thefe rocks in ancient times: 
but this remark does not imply that thefe rocks will 
covfantly wear away ; and I am going to prove to you 
that they will not. If a rocky coaft is of fuch a nature 
as not to he ealily deftrutSlible by the weather, it is co¬ 
vered wit hfea-weeds to the reach of the waves, and above 
with mofs: a cldar proof that fuch a coaf is not wearing 
away. But if the rocks come t.o fall in large'maffes, or 
in general, when any of them decay, the fragments are 
accumulated in tire waterunder them, and the preserv¬ 
ing beach is formed. Then the remaining rocks’them- 
felves differ no more, for preservation, from thofe of our 
mountains.. 
Let 11s now Sum up all the operations which are going- 
forward along our coafs-, and firft, thofe by which our 
continents acquire more extent. The land uiefcafes, ill. 
In the places where the original declivity of the Jhore was 
fuch, that the motion of the waves, in bringing J'and from 
the bottom of the fea, has extended the fraud. 2d. Near 
the mouth of rivers, where the motion of the waves has 
alfo accumulated their fedments along the coafis. 3d. Near 
every part where loofe cliffs have been, or are Hill, falling ; 
where every creek has received, by the currents, all the 
minute materials So fallen; becaufe the currents lofe their 
rapidity in thofe recedes. Thofe are the well-known and 
very great acquiftions of our continents-, which have no 
other compensation by real Ioffes, hut from the retreat of 
ferp coafs ; fo fmall in itfelf that it can hardly he re¬ 
corded any where elfe, but on each Spot, and which is to 
have an end. There is another fort of lofs of our conti¬ 
nents, which has been much infilled upon by thofe au¬ 
thors who have thought, like you, that the fea threatened 
the land-, but that lofs is not real. The new grounds along, 
the coafis are in general very fertile ; and fome have been 
early inclofed : but when that has been done before the 
ground has acquired a Sufficient Solidity, it has funk by 
drying. Storms, then, in a high fea, have broken the 
dikes, and the waves have dallied away the foil ; which 
thereby has been transported to other parts of the coaft. 
This has been the cafe in a manner very dreadful and fa¬ 
tal for thoufands of inhabitants of the coafts of the North 
Sea, but very inconfiderable, comparatively with the 
whole of the acquisitions of thofe coafts. 
From the oppolite operations it is, that, in. confulting 
only hiftorians, you have concluded, “ that it is as gene- 
rally thought that the land is gaining upon the fea, as that 
the fea is gaining upon the land.” But if thefe oppolite de¬ 
cisions are meant to exprefs continuance, they are both 
without foundation: for each of thofe effects has, in its 
nature, a maximum whicli I have explained ; and when it 
ftiall be produced, every coajl, upon the whole, will be 
at ref i I might flop here, in the examination of your 
Theory of the Earth-, for, if our continents cannot be dcjlroycd 
by the known caufes aiding -upon them, they cannot have 
been formed of the materials of other continents deftroyed 
in that manner. However, as it would be difficult to de- 
monftrate, that the duf that probably will continue, in. 
fon.ie meafure, to go out of our continents, (hall be com¬ 
pensated by the increafe of the vegetable earth ; it might 
remain in your mind, that enr land, though thereby gain¬ 
ing in extent, may in. time be levelled with the fore. But 1 
3 C ihall 
