The Vedic fathers of geology

134 Tue Vepic Faruers or Groroey.

While others, led probably by Dr. Croll, maintain. that the Glacial conditions were due to certain Astronomical causes, viz. the elongated ellipse. For, at the present day, the ellipse formed by the FEarth’s orbit is approximately circular in form, but, as supposed by Dr. Croll, it was greatly elongated in the Pleistocene Period. This, it is argued, brings about the alternate glacial and genial periods, and explains the occurrence of warm inter-glacial Epochs, at long intervals, since, every 10,500 years, the physical conditions of the two hemispheres must have been gradually reversed, owing to the precession of the equinoxes. There is yet a third theory promulgated, and according to this, it is believed that, ^ छल if the glacial conditions were due to astronomical causes, there were in reality no relatively warm inter-glacial periods, but merely local advances and retreats of the great Icé-sheet, owing to accidental, local, or annual variations in temperature, snow-fall, and the like”. ( Vide Lapworth’s Text Book of Geolooy. p. 386. Ed. 1899 ).

Be that as it may, the last Glacial Epoch, known as the Great Ice Age, lasted for a considerable period ( vide ante pp. 84, 85 ), and was followed by the Quaternary Era or the Recent period, when Ice-floods having subsided, order