Iiefore the morning, the groiiiul from tlie top of the cliff on the waitr sids
places fifty feet pci pcndicular. The extent of the ground moved was about a
from north to south, and nhout 600 jnids from east to west."
1 the I»
i of what is called the plasli
U ladder I
nd these well-know
the cliff n ear Minster, when tl
¡that grew'iu the m
•ra finna had to be
t doivn tc ..he biped.
> the
The oolitic csearpiiient of the Cotteswolds
sands of the inferior oolite, and the npper lias
arlcs form ths hose.) is also st
i;hispn to present in.iny traces of similar dist
wet season has hci-e, ¡is in the East Devon nndercliff
in the neighbourhood of Cheilcnhaui, at Hewlett's I
Mr. Agg-. this hill is said to he entii-ely composed
f the upper li
Here tl>e phenomena of founders and landslips «ppcai- .. , „„„„^
ire said to be depressed, while twoneres beneath ai-e covered by the masses of earth rol
ng whieh a willow-t.
II the bottom of the slope," i distmee . 0 feet: : side ol
slipped, preserving iu pei'pendicular position.
ti^avorsed h;
Beechenllill, opposit
irregulai
Polfolbioo, a pocficij |<r»oili«tic,n cl
i« marriage of llie W,c <pil)> U, Wdj Uic
•re iovcly Lus, Uiua procceda :
But Msreky grcr'd ihM h
JNT OP LANDSLIPS fSTRICTLY SO CALLED) IN THE HIGHLY
i SILURIAN ROCKS IN SHROPSHIRE AND HEREFORDSHIRE.
1, having been at the ti
rand Wye, ir
onsin England, autl the one which hiis attract
y celebnited by chroniclers, topographers, a
!refor<lsh
-n Sutui-day, February
Euroe'dtommi viUi grid, hL
St loose, o
ched m
:iclies, about half a mile (
of the superficial
ng above a large chasm forty feet
ding down in the diivctlon of the dip towards the valley of Wooiliopc
0 ground continued till the following iVfondav. A chapel which
irown. The tract Is still called itie Wonder,
well-known and considerable landslip occurred at a fiu iu calle.1 the
St of Buildwns Bridge, and about half-way between it and the eiithe
hill which slopes towai-ds the Seven, here exhibits carboninnderlic
the Wenlock limestone, and Inclinc
Between th • morning a
•luding
0 forty I, deep, a,
1, anil foi-eing tl
I the chasm above
.landing. Many fissures
river to excavate for itself a
lie through the meadows, formerly eighty yai-ds on its right bank,
ted a very uneven and corrugated siirlaee, witli elevated and brokeji
were opened in the adjacent gronnd. The Birches larmer
chasm, was moved two or three feet foi tvards, but not
had the cause been an earthqnalte; a contiguous barn.
So vlQlcoU; iic in
=0 CydfT, .p«B)cins of the be.
St have intervened,
ni and western cxtre
)unts the underclift; t
ities of the cl
is, especially on the eastern side, considcitibly
higher than the level of the subsUled masses; at these points therefore the said masses present
nearly vertical escarpments of from fifty to one hundred feet, broken into columnar and irregular
forms; deep fissures also ami gulfs of subsidence extend into the adjoining undercliff in tlie
prolongation of the line of the great chasm. All these features are parlieularly marked on tlic
eastern side, ivhere the singularly bi-oken scenery is represeuted in the views. Plates IV. and V.
We must now proceed to the particular application of the general causcs already indicated in
narlfs, as accounting for simiLir slips, or rather founders of the earth, to the cxicmarkable
exam pie here exhibited of these jihtenomena on the largest scale. M'e
n that in this particular locality a rooky mass of chalk and cherty sandstone,
uui prefiitory i
planation oftli
have already s
varying in thic
thick), presses
posing on imp.
on tiie bcach i
depressed belo
on the beach I
direction, in ai
I beds of loose sand, called fc
H (ac. •dmg i Ì the cl
x I he sea level, though probably very slightl
lelow the ruined cottages, these lias betls ri:
I angle of from 15" to 20°*.
iroughs, pipes, and rifts filled b It grave !Xtena fa
iy cap is
.e subjac, t cheitj
stances let us examine what must be the necessary condition of this deep
IX inouki; the water percolating through its uj>per portion would find vent
3f the ground occupied by it favoured by its configuration the emission of
underclilf being occupied by subsided masses of rock, these would geneagainst
id iiupound the wutc
the inferior portions of the fox mould, check such land-springs,
r, held up by the impervious lias below, thus i-edncing the lower region of
!
[,iiieksand
ave been just describing th
cirmatioil of fc
aseniiauidstate. Now
" drainage in the underksc^
jcoloBical cii
It. »u„ki„>ttav.
n on Ibe (¡uickuid.
he coso &OjipDM<I the quicksud io
ated, tendili) 0 bring down pi
le i-ocky.
washing their piirliclcs fu . Thus
1, when
vely uiidenuined ; and if in any p
of faults in the strata caused a permanent determination of the subterranean c
ese waters in particular lines of direction, the strata adjacent to these lines wci
have a species of vault formed beneath them by this undermining process ; and as
have already seen, tlie lower level by sixty feet of tlie corresponding strata on the southern
Compared with those on the northern side of the chasm, renders the intervention of such fa
very probable. We may heiice leudily conceive tliat tlie superstrata of sandstone unil chalk tl
deprived of support, at the time that their weight was materially augmented by rain-water sa
rating their mass from the exti-eme wetness of the season, would Imve
I their ( ir upon tl
arising fr
actually
oluiniis were brought t.
fluid mass, according to the laws of hydrostatic pressure, modified by the fr
samiy consistence i as this quicksand yieldedf, the incumbent and fractured rocky ma
gradually have sunk deeper and deeper, exactly as tiie phtenoinena are stated to ha'
occurred. If we caleiihite the iliinensions of the chasm, we shall find that nearly 1(
of cubic feet have been left vacanti by the rocks once filling them; and tlie displacement of
sand from the yielding and seiiiifliiid substrata could not have been much less (making only
some allowance for tlie previous vacuities of undermining). We may form some idea of the
immense lateral pressure that resulted from such a cause, and to this lateral pressure we may
with the most probability refer the elevation of the submarine beach, to the description and
theory of which we shall next proceeil; but before doing so it will be most convenient to invite