वेदों की प्राचीनता एवं काल-निर्णय / ओरायन (लोकमान्य बाल गंगाधर तिलक - खगोलीय वैदिक शोध)

PREHISTORIC TIMES. ii
Bronze and Iron, cannot be separated very sharply from each
other. But taken as a whole we can clearly distinguish one era
from another by its characteristic 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, begin-
ning 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 ... ... { Cretaceous.
Jurassic.
Triassic.
Primary or Palæozoic ... ... { Permian.
Carboniferous.
Devonian, and Old
Red Sandstone.
Silurian.
Cambrian.
Archæan or Eozoic ... ... ... Fundamental Gneiss.
Thus the oldest of the stratified rocks at present known is
the Archæan or Eozoic. Next in chronological order come
the Primary or the Palæozoic, the Secondary or the Mesozoic,
the Tertiary or Cainozoic, and last the Quarternary. The
Quaternary era, with which alone we are here concerned, is
subdivided into the Pleistocene 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 Gla-
cial 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