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