9. Millions of forest-trees sprang up, towered to heaven, and fell, to be crushed into the coal strata which make our winter fires. Hundreds of feet measure the thickness of what were once succulent plants, but pressed together like paper-pulp, and consolidated under a weight absolutely immensurable. Yet there remain the scales of their stems, the elegant reticulated patterns of their bark, the delicate tracery of their leaf-nerves, indelibly depicted by an unpatented process of "nature-printing." And when we examine the record,--the forms of the leaves, the structure of the tissues, we get the same result as before, that the plants belonged to a flora which had no species in common with that which adorns the modern earth. Very gradually, and only after many successions, not of individual generations, but of the cycles of species, genera, and even families, did the vegetable creation conform itself to ours.[48] 10. At length the species both of plants and animals grew,--not by alteration of their specific characters, but by replacement of species by species--more and more like what we have now on the earth, and finally merged into our present flora and fauna, about the time when we find the first geological traces of MAN. 11. During the course of these successive cycles of organic life, the map of the world has changed many times. Up to a late period the ocean washed over Mont Blanc and Mount Ararat; the continent of Europe was a wide sea; then it was a Polynesia, then an Archipelago of great islands, then a Continent much larger than it is now, with England united to it, and the solid land stretching far away into the Atlantic;--then it sank again, and was again raised, not all at once, but by several stages, each of which has left its coast line, and its shingle beach. All these changes must have been the work of vast periods of time.