Page 222 - Lokmanya Tilak Samagra (khand 2)

PREHISTORIC TIMES 9
cannot be separated very sharply from each other. But taken as a
whole we can clearly distinguish one era from another by its cha-
racteristic fossil remains. Each of these geological ages or eras is
again subdivided into a number of different periods. The order of
these Eras and Periods, beginning with the newest, is as follows :-
Eras. Periods.
Post-Tertiary or Quaternary ... Recent ( Post-Glacial )
Pleistocene ( Glacial )
Tertiary or Cainozoic Pliocene
Miocene
Oligocene.
Eocene
Secondary or Mesozoic ... Cretaceon
Jurassic
Triassic
Primary or Palreozoic Permian
Carboniferous
Devonian, and Old
Red Sandstone.
Silurian
Cambrian.
Arch rean or Eozioc Fundamental Gneiss.
Thus the oldest of the stratified rocks at present known is the
Archrean or Eozoic. Next in chronological order come the Primary
or the Palreozoic, the Secondary or the Mesozoic, the Tertiary or
Cainozoic, and the last Quaternary. The Quaternary era, with
which alone we are here concerned, is sub-divided into the pleis-
tocene or the Glacial, and the Recent or the Post-Glacial period,
the close of the first and the beginning of the second being marked
by the last Glacial epoch, or the Ice Age, during which the greater
portion of northern Europe and America was covered with an ice-
cap several thousand feet in thickness. The Iron age, the Bronze
age, and the Neolithic age come under the Recent or the post-
Glacial period, while the Palreolithic age is supposed to fall in the
Pleistocene period, though some of the palreolithic remains are
post-Glacial, showing that the palreolithic man must have surviv-
ed the Ice Age for some time. Latest discoveries and researches
enable us to carry the antiquity of man still further by establi-
shing the fact that men existed even in the Tertiary era.