44
PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .JuilG 14,
part of the Barton clays near Hordwell is well known, but in descend-
ing lower in the strata they become much scarcer, and almost entirely
disappear at the base of these clays. The strata also become gene-
rally more mixed with sand, much of which consists of greensand. At
the end of the cliif near High-cliff House, nearly one mile east of
Muddiford, we have the following section, fig. 1 .
Section near the West end of Barton Cliff,
w. E, Fig. 1.
Ft. in.
Ochreous flint gravel. .
Dark grey sandy clays with imperfect vegetable re- I Lower part
mains. ... I ^^ ^^^
Tabular soft septaria mixed with greensand. f Barton clay
Clayey greensand with a few indistinct impressions series.
of shells and a few pebbles.
Rounded flint pebbles in light-coloured sand.
Light grey clayey sand full of car-
bonized small fragments of vege-
tables.
Irregular band of sandstone.
Same as above the sandstone, but
rather lighter and more sandy.
Light brown and yellow clayey
sand with imperfect vegetable
( impressions.
The upper part of this bed
thins out as it trends
westward, whilst the
lower part loses its bitu-
minous clay and passes
into a fine whitish and
yellow sand full of the
same carbonized frag-
ments of vegetables.
If the strata at the Barton cliffs and those at Hengistbury Head
were on the same line of strike, and no fault intervened, we might
expect to find at the latter place beds lower in the series than those
we left at the former ; but it will be perceived that Hengistbury Head
projects south in advance of the general line of coast, and conse-
quently is not in the same bearing of the strata as the Barton Cliffs.
At Hengistbury Head the strata are more in the trough of the syn-
clinal line of which the anticlinals of the Isle of Wight and Isle of
Purbeck form the southern edge. This may, I think, account,
without any disturbance, for the reappearance of the Barton clays on
the other side of Christchurch Harbour at Hengistbury Head. I
have little to add to Sir Charles Ly ell's description of the cliffs at
this place, and beg to refer to his paper for fuller details than I pur-
pose entering into. I would venture however to introduce the group-
ing shown in the section fig. 2.
In examining this section we find a near lithological resemblance
to the cliff east of Muddiford. The difference is no greater than is
common at like distances in any beds of this varying series. The
same general characters are preserved, but some slight details vary.
The sands at the base of both sections are exactly alike in appearance,
and present in both places the same peculiar fragmentary and carbo-