rms of life were both well developed and individually
numerous. Among the insects we find the Orthoptera, Neuroptera,
Hemiptera and Coleoptera represented; cockroaches were particularly
abundant; crickets, beetles, locusts, walking-stick insects, mayflies
and bugs are found, but there were neither flies, moths, butterflies
nor bees, which is no more than we should expect from the conditions
of plant life. Many insects, &c., have been obtained from the
coalfields of Saarbruck and Commentry, and from the hollow trunks of
fossil trees in Nova Scotia. Certain British coalfields have yielded
good specimens: _Archaeoptilus_, from the Derbyshire coalfield, had a
spread of wing extending to more than 14 in.; some specimens
(_Brodia_) still exhibit traces of brilliant wing colours. In the Nova
Scotian tree trunks land snails (_Archaeozonites, Dendropupa_) have
been found.

In the later Carboniferous rocks the earliest amphibians make their
appearance in considerable numbers; they were all Stegocephalians
(Labyrinthodonts) with long bodies, a head covered with bony plates
and weak or undeveloped limbs. The largest were about 7 or 8 ft. long,
the smallest only a few inches. Some were probably fluviatile in habit
(_Loxomma, Anthracosaurus, Ophiderpeton_); others may have been
terrestrial (_Dendrerpeton, Hylerpeton_). Certain footprints in the
coal measures of Kansas have been supposed to belong to lacertilian or
dinosaurian forms.

_The Physical Conditions during the Period._--In western Europe the
advent of the Carboniferous period was accompanied by the production
of a series of synclines which permitted the formation of organic
limestones, free from the sediments which generally characterized the
concluding phases of the preceding Devonian deposition. The old land
area still existed to the north, but doubtless much reduced in height;
against this land, detrital deposits still continued to be formed, as
in Scotland; while over central Ireland and central and northern
England the clearer waters of the sea furnished a suitable home for
countless corals, brachiopods and foraminifera and great beds of sea
lilies; sponges flourished in many parts of the sea, and their remains
contributed largely to the formation of the beds of chert. This
clearer water extended from Ireland across north-central England and
through South Wales and Somerset into Belgium and Westpha