1848.. PRESTWICH ON STRATA OF CHRISTCHURCH HARBOUR. 45
Section of the Cliff at Hengistbury Head.
Fig. 2.
Feet
Ochreous flintgravel.
Sandy clays.
White clayey sands full
of vegeta )ie remains.
Clay much mixed with
sands, white & green.
Dark grey clay much
mixed with patches of
greensand.
Rounded flint pebbles
in white sand.
These beds form one se-
ries, and pass one into
the other. It contains
large, flat, very ferru-
ginous septaria full of
carbonized vegetable
fragments and with a
very few casts of shells.
In the lower bed of
clay casts of shells are
also very rarely found,
but in parts of the clays
above they are not un-
common; a few pebbles
occur throughout.
Whitish sand full of small fragments of carbonized vegetable
remains. About ^ mile west of the headland the car-
bonaceous matter so greatly increases, that the upper part
of the sand for a thickness of 5 feet passes into a black
carbonaceous sand. The thickness of this stratum is
not seen in this part of the cliflFs.
have the same well-marked bed of black flint pebbles, varying in size
from a marble to a swan's egg, and imbedded in white and yellow
sand and forming a perfect gravel-bed. Above these are the clays,
rather more sandy, it is true, at Hengistbury Head than in Barton
cliff and the septaria more ferruginous, but with no character of any
value as indicating difference of origin. In further corroboration we
have the evidence, scanty though it be, of organic remains. In the
lower part of the clay at Hengistbury Head they are extremely
scarce : I only found one cast of a small Modiola and some teeth of
the Lamna. Rather higher in the section, and at a short distance
west of the Head, I however found very friable, but abundant re-
mains of Barton clay species of Panopsea, Solen, Cytherea, Pectun-
culus and Venericardia. Of themselves these few fossils would be
insufficient to determine the age of these clays. Several of them
equally mark the Bracklesham beds, though on the whole they pro-
bably more resemble those of the Barton clays ; but this fact being
supported by a superposition and by lithological characters, agreeing
with the lower beds of the Barton clay at Barton, it follows that the
weight of evidence is in favour of their belonging to this series. I
had not time to work out more fully the organic remains of this bed,
but a further search would, I am convinced, bring many more to
light. There is a brick-pit recently opened immediately on the eastern
side of the headland, at which I requested the men to collect any
specimens they might meet with.
The septaria, although containing almost exclusively carbonized
fragments of plants and imperfect vegetable impressions, also showed
traces here and there of shells. The *' Teredo antenauta " was far
from uncommon in some of the large fossil stems of trees which are
found both in the clays and in the septaria. I would also call atten-