ricity has been almost always much
higher than {89} it is now, we should expect that the quantity of ice in
the southern hemisphere will usually have been greater, and will thus have
tended to increase the force of those oceanic currents which produce the
mild climates of the northern hemisphere.

_Evidences of Climate in the Secondary and Palaeozoic Epochs._--We have
already seen, that so far back as the Cretaceous period there is the most
conclusive evidence of the prevalence of a very mild climate not only in
temperate but also in Arctic lands, while there is no proof whatever, or
even any clear indication, of early glacial epochs at all comparable in
extent and severity with that which has so recently occurred; and we have
seen reason to connect this state of things with a distribution of land and
sea highly favourable to the transference of warm water from equatorial to
polar latitudes. So far as we can judge by the plant-remains of our own
country, the climate appears to have been almost tropical in the Lower
Eocene period; and as we go further back we find no clear indications of a
higher, but often of a lower temperature, though always warmer or more
equable than our present climate. The abundant corals and reptiles of the
Oolite and Lias indicate equally tropical conditions; but further back, in
the Trias, the flora and fauna, in the British area, become poorer, and
there is nothing incompatible with a climate no warmer than that of the
Upper Miocene. This poverty is still more marked in the Permian formation,
and it is here that some indications of ice-action are found in the Lower
Permian conglomerates of the west of England. These beds contain abundant
fragments of various rocks, often angular and sometimes weighing half a
ton, while others are partially rounded, and have polished and striated
surfaces, just like the stones of the "till." They lie confusedly bedded in
a red unstratified marl, and some of them can be traced to the Welsh hills
from twenty to fifty miles distant. This remarkable formation was first
pointed out as proving a remote glacial period, by Professor Ramsay; and
Sir Charles Lyell agreed that this is the only possible explanation that,
with our present knowledge, we can give of them.

Permian breccias are also found in Ireland, containing {90} blocks of
Silurian and Old Red sandstone rocks which Professor Hull believes could
only have been carried by floating ice. Similar breccias occur i