to come to mature life. This waste of creative energy can only be defended on the plea that the survival of the fittest improves the future status of the successful competitors.
Biologists conversant with fossil records inform us that the life-histories of the great animal groups which now inhabit the earth have a wide range both in space and time. Invertebrates, of course, go back to pre-Cambrian times, but the Vertebrates are of more recent date. First, in ascending order, come Fishes (Silurian); then amphibians (Carboniferous); then Reptiles (Permian); then Birds and Mammals (Jurassic and Triassic respectively); but not till towards the close of the Tertiaries have we clear evidence of the presence of Man on the globe. All these geological formations, with their characteristic fossils, are to be found within the confines of the Britain of to-day.
Plants.—The evolution theory applies equally to the Vegetable Kingdom. In some respects the consecutive stages in the geological history of plants may be paralleled with those of animals. But the details of palæobotany are more difficult to decipher (see Evolution of Plants by D. H. Scott in this Library), and wide generalizations have hither-to been scanty. For our present purpose it is, however, enough to know that the members of the sub-Kingdom of the Angiosperms, or Flowering Plants, are not only the most recent in point of evolution, but the most numerous in the vegetable world of to-day. They em-
