206 
sion which has thrown the strata into 
a vertical position. Thus, although 
at Allum Bay and White Cliff, these 
beds appear in a vertical position in 
the face of the cliffs; yet at Newport, 
the stratification of this series is nearly 
horizontal, as proved by excavations 
made near that town. From some sec- 
tions of the opposite coast, at Lyming- 
ton and Poole, the beds of plastic clay 
and sand also appear in a horizontal 
position. The beds of similar forma- 
tion, and, in all probability, of simul- 
taneous formation in the London basin, 
as at Plumstead, at Reading and other 
places, also lie very nearly horizentally 
between the blue clay and the chalk. 
Tn conjunction with, but to the south- 
ward of, the before-mentioned beds, 
follows the great ridge of chalk, which 
extends, east and west, through the 
whole island. But the most remark- 
able fact, connected with this chalk 
formation, is that of its great inclina- 
tion with the horizon. The elevation of 
the chalk stratum seems, however, to 
have been nearly the boundary of the 
great conyulsion which produced the 
disruption of the strata; for the south 
and south-west sides of the chalk hills 
slope gradually away to the horizon, 
and have suffered a similar kind of de- 
nudation, ‘or excavation of the sur- 
face, as is apparent in the chalk ranges 
of Kent and Sussex, by which the lower 
strata are exhibited in the yallies or 
wealds. 
Some obseryations in Dr. Fitton’s 
valuable paper, ‘relative to the “ Beds 
between the Chalk and the Purbeck 
Limestone,” published in a late number 
of the Annals of Philosophy, decidedly 
prove the Isle of Wight to have been 
subject to some great convulsion, which 
scarcely affected any other part of our 
coast. ‘ Speaking of the green-sand de- 
posite, Dr. F. says: 
*© One feature of this formation, which is 
very conspicuous on the coast of the Isle 
of Wight, and might lead into error, in 
situaticns less favourable for examination, 
consists in the great variation of aspect and 
solidity in different portions of the same 
continuous beds—one part not unfrequently 
appearing as a very dark greenish, or al- 
most black, sandy clay; while the very same 
bed has, in other places, where the fracture 
is recent, a bright reddish or yellowish hue. 
This appearance has been noticed by Sir H. 
Englefield and Mr. Webster, and is ascribed 
by them, I believe correctly, to the effects 
of moisture and exposure on the variable 
proportion of clay and. ferruginous ‘matter 
whieh the beds every where seem to con- 
tain. 
Geolosy of the Isle of Wight. 
[Apr. I, 
With regard to the lower strata found 
in the south-west of the Isle of Wight, 
Dr. Fitton considers it as varying from 
the sand rock of Hastings (with which it 
has been identified by previous geolo- 
gists) by the character of the fossils it 
contains. After enumerating a list of 
these fossils, he observes: 
“* A comparison even of this short list 
with that of the green sand fossils (of the 
island), points out a distinction between 
that formation and the Hastings’ sands, 
which may perhaps, deserye attention in 
the grouping and arranging of the strata; 
the organized productions of the former, so 
far as we are acquainted with them, being 
all marine, but, of the latter, almost ex- 
clusively, of fresh-water origin. And, in 
fact, if a line be drawn between the green 
sand and the weald clay, the whole series 
from thence down to the Portland lime- 
stone may be regarded as one great suite 
of fresh-water formations.”’ 
So that part of the series has evidently 
been displaced or elevated from the 
bed of an extensive fresh-water lake ; 
while other parts appear to have fallen 
into the chasm, produced by the erupe 
tion. No other agency, but volcanic, 
with which we are acquainted, could 
have accomplished such stupendous re- 
sults; and that such a catastrophe has 
occurred at some remote period, the 
following observations of Mr, Webster, 
“On the Chalk Formation of the 
Island,” places. further beyond a doubt: 
“* All the flints, except those detached 
nodules in the body of the strata, are uni- 
versally found in a most extraordinary 
state: they are broken in every direction 
into pieces of every size, from three inches 
diameter to an absolutely impalpable pow- 
der. ‘The flints, as if shivered by a blow 
of inconceivable force, retain their complete 
form and position in their bed; the chalk 
investing them on every side, and until it 
is removed, nothing different from other 
flints can be perceived, excepting fine lines 
indicating their fractures; but, when re- 
moved, they all at once fall to pieces. The 
fragments are all as sharp as possible, and 
quite irregular, being certainly not the 
effect of any crystallization, or-internal ar- 
rangement of the materials, but merely of 
external violence. This new and most ex- 
traordinary appearance was first observed 
in a small pit on the Shorwell road, just 
beyond the parting of the road to Yar- 
mouth. But no opportunity was after- 
ward omitted of examining both the cliffs 
and the pits, in many parts of the whole 
range of chalk, and the appearances were. 
every where, nearly similar; differing only 
in the circumstance, that in some. places 
the flint appeared to be more completely 
shattered than in others.” : 
t 
