Hill and The Barn, appear to have been noticed first by Mr. Seale,*
who thought the shells were of marine origin; and this opinion was
shared by Lamarck and others for some time, hut their true character
■was subsequently discovered. The late Professor Edward Porbes,
E.R.S., in reference to ten species of them, writes as follows :f—
“ Of five subfossil Bulimi, the affinities of two are decidedly and
remarkably South American. The Bulimus auris-vulpina is unlike any
•old-world form, and its relations must be sought for in the Brazilian
B. bilabiatus, and probably B. melanostoma and its allies. Eor allies
of the equally peculiar Bulimus darvinianus we must also go to Brazil
and compare with B. goniostonia and similar types. Of the other
two, the affinities are with species now living in St. Helena.
Bulimus sealeianus is nearly allied to Bulimus helena of Beeve (not
pf Quoy) and the Achatina exulata of Benson. Cocldigena fossilis of
Sowerby is allied to this, but very distinct. Bulimus blofeldi is
nearly allied to an existing undescribed species found by Mr.
Alexander feeding on the cabbage-trees only on the highest points
of the Island, The affinities of the latter are decidedly West
African; those of the former point in two directions, African and
South American, the latter character possibly prevailing.
“ An Achatina, called Cocklicopa subplicata by Mr. Sowerby, is
chiefly connected with West Indian forms, but has also relations on
the West Coast of Africa, such as the A. clavata of Sierra Leone.
Mr. Sowerby described an allied species under the name of Cochli-
copa terebellum.
“ The subfossil Succinea is of a very ordinary character, as is
the case with the majority of species of this genus all the world
over, though, curiously enough, one of the living St. Helena
Succinea is remarkable for its peculiarities.
“ One of the Helices is most nearly related to Madeiran types.
Mr. Sowerby has described four species, IT. bilamellata, H. polyodon,
H. spurca, and H. biplicata, in his note on Mr. Darwin’s collection.
I have examined the first and third of these.
“ I have endeavoured elsewhere! to show that all the information
we "possess respecting the Marine Mollusks of the coast of St.-
Helena would lead us to infer the very ancient isolation of that
* Geognosy of the Island of St. Helena, by Mr. Seale,
t Proceedings of Geological. Society, March 10th, 1852, p. 1961.
Rep. Brit. Assoc, for 1851.
Island, whilst at the same time a pre-existing closer geographical
relationship between the African and American continents than now.
maintains is dimly indicated. The information we have obtained,
respecting the extinct and existing terrestrial mollusks of this iso-,
lated fragment of land would seem to point in the same direction,
and assuredly to indicate a closer geographical alliance between St..
Helena and the west [? east] coasts of South America than now holds.”'
Mr. J . H. Blofeld, F.Gr.S.. also records, in reference to the conditions
under which he found these subfossil shells of St. Helena,:
about half a mile behind Longwood, at an elevation of about 1700
feet above the sea, on a hill-side worn into numerous clefts or ravines
by the heavy rains, as follows :*—“ The shells are met with in
various elevated parts of the Island.. The surface of the hill to a
depth of five to six feet consists of dark mould, and under this is a
stratum of a greyish-brown friable earth about three to four feet
thick; in this latter bed the shells occur.f This earth also contains
bird-bones,J perfect and fragmentary, in abundance; and it was
suggested that possibly in some cases the shells may have been
brought to the spot by birds that fed on their living occupants.
“ The B. auris-vulpina is accompanied by B: subplicata and Helix-
bilamellata- In the ‘ shell-bed’ are found numerous lumps of
; several sizes, composed of a white powdery substance, and associated
with a harder yellow substance.§ Some specimens of a new species
o f Bulimus (B. blofeldi, E. Eorbes) were found (together with some
young Helix bilamellata) in a reddish clay or loam on the side of a
* Proceed. Geol. Soc.-, March 10, 1852, p. 195.
t “ This deposit is composed chiefly of vegetable- matter and carbonate of lime. The
latter is present, both in'the form of prismatio crystals (shell tissue ?) and as the coating of
vegetable fibres. The majority of the specimens of B. auris-aulpma presented to the Geological
Society’s Museum bjr the late Mr. Seale, P.G.S., were embedded in a whitish coherent
: . sand, consisting of grains (chiefly inorganio) coated with calcareous matter.”
I t “ Professor Owen, having examined these bones, pronounces them to belong to marine
birds. The Professor has also examined some specimens of similar hones from Turk’s Cap
Bay, St. Helena, presented to the Geological Sooiety by Captain Wilkes, B.N. These also are
all bones of marine birds, most of. them being of the Petrel kind; some of.them belon» to-the
snbgenus Puffinus. The bones from Turk’s Cap Bay are from a greyish-brown° earthy
deposit, containing much inorganio, sand, the grains of which are partially coated with '
calcareous matter.” .
§ “ This white substance has been chemioally examined by Dr. Percy, PGS who
observes, that it consists of matter-soluble in nitric aoid with effervescence, with the exception
of a small quantity of insoluble residue, probably siliceous. The soluble matter is carbonate
of lime, sulphate of lube, carbonate of magnesia, and phosphoric acid in combination with s»so„i
. oxide of iron. The harder yellow portion wan. found to contain organic matter, possibly
cause of the yellow colour, and to be similar in constitution with the white powder "