356 
Mr. Lyell on the Boulder Formation^ 
R. C. Taylor, who had opportunities of observing them at 
low tide as being continuous with the solid bed of chalk ex- 
tending under the sea for nearly a mile from Trimmingham 
to Sidestrand, constituting everywhere under water a level 
platform. He also says that the chalk of this platform con- 
tains throughout parallel strata of flint, is harder than that of 
Cromer or Norwich, is characterized by several peculiar fossils, 
and occupies, he thinks, a higher place in the series than the 
chalk at Norwich*. 
Now the platform here alluded to is evidently what the 
sea has left after sweeping away by gradual denudation all 
that once rose above low water, and it is therefore impossible 
for us now to conjecture to what height the chalk thus removed 
may once have risen. The most southern of the three protu- 
berances before mentioned occurs near the Beacon hill, about 
half way between Mundesley and Trimmingham, and it is in 
contact with stratified drift the beds of which are highly in- 
clined. The mass of chalk is about 20 feet in height, its ex- 
tent along the beach about 100 feet, and its thickness from 
the beach inland a few yards only. It stands up like a nar- 
row wall, which will ultimately be destroyed, and then the 
whole face of the cliff will consist of clay sand and gravel. 
The surface of this wall of chalk, where in contact with the 
drift, dips inland at an angle of about 45°, and the beds of 
the newer deposit conform to this slope. As the chalk offers 
more resistance to the waves than the drift, a small promon- 
tory is produced at this point, which projects about 40 feet 
beyond the general coast line, and by aid of this promon- 
tory we are able to see the junction of the chalk and newer 
beds, both on the north and south side, so that the relative 
position of the two formations is very clearly ascertained 
(see fig. 6.) 
When 1 visited this spot in 1829, I found the cliff nearly 
in the same state as it remained in 1839, and the description 
which I gave of it in the Principles of Geology would still be 
appropriate t- 
But when last there I was able to examine the entire struc- 
ture of this cliff more thoroughly, and I was more fully con- 
firmed in my opinion that both the chalk and incumbent for- 
mation, for the thickness of several hundred feet, must have 
been subject to some common movement, whether sudden or 
gradual, by which the strata of both have been tilted. 
The annexed view of the promontory (fig. 6.) was taken 
from a point on the sloping cliff a few hundred yards to 
the south, where the beds have already recovered their hori- 
* Gcol. 'rraiis., vol. i. 2iul series, [>. 37()- 
t Vol. iii. Ibt edit. p. ]7J)j or .51 li edit. vol. iv.p. 85. 
