File:The Quarterly journal of the Geological Society of London (12895096653).jpg

1864..
SEELEY — HUNSTANTON RED ROCK.
329
sponge-rock, though only in patches. There are many fissures in
this stratum and in the chalk, which pass down to the top of the
Red Rock; they are filled with black and red colouring-matter,
often largely mixed with recldish-brown sand. At the base the red
matter thickens, and generally enlarges into nests.
Bearing on this subject is the section (fig. 1), showing a slight slip
in the Red Rock and Carstone, which has not affected the chalk,
except by shivering it, and by forming fissures which are filled in as
shown in the figure. The top of the sponge-rock is merely curved

and where the Red Rock is in the middle of the cliff is the section
given in fig. 2. Under 8 inches of top earth are about 9 feet of re-
constructed chalk, quite white, and seemingly without any foreign
substance. Below this is about 20 feet of chalk, then the sponge-
band, and finally the Red Rock. From the top of this latter up to
the reconstructed chalk extends a straight but obliquely inclined
fissure, which expands at the top, trumpet-like, to a width of at least
3 feet, and similarly expands at the base to a length of 4 feet, form-
ing a triangular mass which displaces the sponge-band entirely, and
some of the grey sandy chalk. This fissure and its expansions are
filled with red matter, which is darkest in the line of the fissure and
at its base.
Fig. 1. — Section showing a fault in the Red Rock and Carstone, the
Sponge-bed being shattered.
w A. Fine drab-coloured sand.
B. Yellow sand with black par-
ticles.
C, D. Ochreous sand with black
particles.
E. Deep-red matter.
W. Grey sandy chalk.
X. Sponge-bed.
Y 1 , Y 2 , Y 3 . Red Rock.
Z. Carstone.
lipii
ii
ii
Fig. 2.
Section showing a fissure in the CJialJc of Hunstanton con-
taining red matter.
a. Earth.
b. Reconstructed chalk, 4 ft. thick.
c. White chalk.
d. Band of red chalk.
e. Grey sandy chalk.
/. Sponge-bed.
g. Red