sturbance. There is another
mass of land far to the southeast of this Scandinavian island, which we
may designate as the Bohemian island, for it lies in the region now called
Bohemia, though it includes, also, a part of Saxony and Moravia. The
northwest corner of France, that promontory which we now call Bretagne,
with a part of Normandy adjoining it, formed another island; while to the
southeast of it lay the central plateau of France. Great Britain was not
forgotten in this early world; for a part of the Scotch hills, some of the
Welsh mountains, and a small elevation here and there in Ireland, already
formed a little archipelago in that region. By a most careful analysis of
the structure of the rocks in these ancient patches of land, tracing all
the dislocations of strata, all the indications of any disturbance of the
earth-crust whatsoever, Elie de Beaumont has detected and classified four
systems of upheavals, previous to the Silurian epoch, to which he refers
these islands in the Azoic sea. He has named them the systems of La
Vendee, of Finistere, of Longmynd, and of Morbihan. These names have, for
the present, only a local significance,--being derived, like so many of
the geological names, from the places where the investigations of the
phenomena were first undertaken,--but in course of time will, no doubt,
apply to all the contemporaneous upheavals, wherever they may be traced,
just as we now have Silurian, Devonian, Permian, and Jurassic deposits in
America as well as in Europe.

The Silurian and Devonian epochs seem to have been instrumental rather in
enlarging the tracts of land already raised than in adding new ones; yet
to these two epochs is traced the upheaval of a large and important island
to the northeast of France. We may call it the Belgian island, since it
covered the ground of modern Belgium; but it also extended considerably
beyond these limits, and included much of the Northern Rhine region. A
portion only of this tract, to which belongs the central mass of the
Vosges and the Black Forest, was lifted during the Silurian epoch,--which
also enlarged considerably Wales and Scotland, the Bohemian island, the
island of Bretagne, and Scandinavia. During this epoch the sheet of water
between Norway and Sweden became dry land; a considerable tract was added
to their northern extremity on the Arctic shore; while a broad band of
Silurian deposits, lying now between Finland and Russia, enlarged that
region.