lia; but a
narrow ridge of elevated older rocks ran across the centre of England
towards Belgium at this time.

Traced eastward into north Germany, Thuringia and Silesia, the
limestones pass into the detrital culm formations, which owe their
existence to a southern uplifted massif, the complement of the
synclines already mentioned. Sediments approaching to the culm type,
with similar flora and fauna, were deposited in synclinal hollows in
parts of France and Spain.

Thus western Europe in early Carboniferous time was occupied by a
series of constricted, gulf-like seas; and on account of the steady
progress of intermittent warping movements of the crust, we find that
the areas of clearer water, in which the limestone-building organisms
could exist, were repeatedly able to spread, thus forming those thin
limestones found interbedded with shale and sandstone which occur
typically in the Yoredale district of Yorkshire and in the region to
the north, and also in the culm deposits of central Europe. The spread
of these limestones was repeatedly checked by the steady influx of
detritus from the land during the pauses in movements of depression.
Looking eastward, towards central and northern Russia, we find a wider
and much more open sea; but the continental type of deposit prevailed
in the northern portion, and here, as in Scotland, we find coal-beds
amongst the sediments (Moscow basin). Farther south in the Donetz
basin the coals only appear at the close of the Lower Carboniferous.

In North America, the crustal movements at the beginning of the period
are less evident than in Europe, but a marked parallelism exists; for
in the east, in the Appalachian tract, we find detrital sediments
prevailing, while the open sea, with great deposits of limestone, lay
out towards the west in the direction of that similar open sea which
lay towards the east of Europe and extended through Asia.

The close of the early Carboniferous period was marked by an
augmentation of the orogenic movements. The gentler synclines and
anticlines of the earlier part of the period became accentuated,
giving rise to pronounced mountain ridges, right across Europe.

This movement commenced in the central and western part of the
continent and continued throughout the whole Carboniferous period. The
mountains then formed have been called the "Palaeozoic Alps" by E.
Kayser, the "Hercyn