COURSE OF LIFE Q17

upon them, and picture their appearance in the various stages of their history.

In that remote time, which we have roughly taken as a hundred million years ago, when the oldest rocks, those for instance at Gulmarg, were first laid down in level soft deposit on the ocean bottom, there was no life on land or sea. In no part of the world have the rocks of this period given the slightest trace of any form of life. But in the course of time, in some warm climate and in some quarter where sea and land meet, and where, through the action of the tides, a portion of the land is alternately covered and laid open to the sunshine—that is, in some spot where earth and air, light, heat and water might all have their effect— it has been surmised that minute microscopic specks of slime must have appeared imbued with just that mysterious element which distinguishes life from all chemical combinations however complex.

Of this initial stage, which would not have been perceptible to the naked eye, no trace could possibly be left, but in the pre-Cambrian rocks in Europe there have been detected very minute specimens of the simplest known forms of life— the Protozoa—and obscure tracks and markings indicating the existence of life of some kind. And