about fossils, and of the way in which they tell us the kind of life that existed when they were first sunk in the rocks where now they are found, and how also they give us information about the climate and the distribution of land and sea, of lake and of river, in those eras far "in the backward and the dark abyss of time." [Illustration: _Stereo Copyright, Underwood & U._ _London and New York_ The Pinnacled Castle-like Peaks of the Ramshorn Mountains Of Wyoming The successive strata of sandstone are clearly evident in the peaks.] For the present, however, we may concern ourselves with the condition of the earth and its rocks in Proterozoic times, observing merely that the remains of animals which we find there are of an order (Crustacea) which shows that life had progressed a good deal from its earliest beginnings in the age when the rocks containing these crustacea were laid down. After these rocks had been deposited they were subjected to many influences of which we have only dim conceptions. In a previous chapter we have compared the layers of the undermost and harder rocks of the earth to the lines on a page of this book as they would appear if the pages were crumpled up into a ball. Sometimes the beds of solid rock have been so distorted that they look like waves of the sea; sometimes they have been completely overturned; hardly ever have they been suffered to lie down flat. More than that has happened to them. Their very nature has been changed. This was done partly by heat, partly by pressure, partly by shock.