ribution of
Mollusca.' It is plain that of all animals, land-shells and
reptiles give the surest tokens of any former connection of islands,
being neither able to swim nor fly from one to another, and very
unlikely to be carried by birds or currents. Judging, therefore, as
he has a right to do, by the similarity of the land-shells, Mr.
Bland is of opinion that Porto Rico, the Virgins, and the Anguilla
group once formed continuous dry land, connected with Cuba, the
Bahamas, and Hayti; and that their shell-fauna is of a Mexican and
Central American type. The shell-fauna of the islands to the south,
on the contrary, from Barbuda and St. Kitts down to Trinidad, is
South American: but of two types, one Venezuelan, the other
Guianan. It seems, from Mr. Bland's researches, that there must
have existed once not merely an extension of the North American
Continent south-eastward, but that very extension of the South
American Continent northward, at which I have hinted more than once
in these pages. Moreover--a fact which I certainly did not expect--
the western side of this supposed land, namely, Trinidad, Tobago,
Grenada, the Grenadines, St. Vincent, and St. Lucia, have, as far as
land-shells are concerned, a Venezuelan fauna; while the eastern
side of it, namely, Barbadoes, Martinique, Dominica, Guadaloupe,
Antigua, etc., have, most strangely, the fauna of Guiana.

If this be so, a glance at the map will show the vast destruction of
tropic land during almost the very latest geological epoch; and
show, too, how little, in the present imperfect state of our
knowledge, we ought to dare any speculations as to the absence of
man, as well as of other creatures, on those great lands now
destroyed. For, to supply the dry land which Mr. Bland's theory
needs, we shall have to conceive a junction, reaching over at least
five degrees of latitude, between the north of British Guiana and
Barbadoes; and may freely indulge in the dream that the waters of
the Orinoco, when they ran over the lowlands of Trinidad, passed
east of Tobago; then northward between Barbadoes and St. Lucia; then
turned westward between the latter island and Martinique; and that
the mighty estuary formed--for a great part at least of that line--
the original barrier which kept the land-shells of Venezuela apart
from those of Guiana. A 'stretch of the imagination,' doubtless:
but no greater stretch than will be required by any e