The Outline of History: Being a Plain History of Life and Mankind

the World. § 3. An Age of Brain Growth. § 4. The Wo

phases of great warmth, intense cold, and extreme dryness; but the landscape, if it altered, altered to nothing that cannot still be paralleled to-day in some part of the world or other. In the place of the cycads, sequoias, and strange conifers of the Mesozoic, the plant names that now appear in the lists of fossils include birch, beech, holly, tulip trees, ivy, sweet gum, bread-fruit trees. Flowers had developed concurren

d, a gigantic crumpling of the earth's crust and an upheaval of mountain ranges was in progress. The Alps, the Andes, the Himalayas, are all Cainozoic mount

(but little of recent life), in which the climate was still equable. The Miocene (with living species still in a minority) was the great age of mountain building, and the general temperature was falling. In the Pliocene (more living than extinct species), climate was very much at its present phase

the first time a variety and abundance of mammals. Before we proceed to any descr

nt from water; it is an amphibian that is no longer amphibious; it passes through its tadpole stage-its fish stage, that is-in an egg. From the beginning it must breathe in air; it can never breathe under water as a tadpole can do. Now, a modern mammal is really a sort of reptile that has developed a peculiarly effective protective covering, hair; and that also retains its eggs in the body until they hatch so that it brings forth living young (viviparous), and even after birth it cares for them and feeds them by its mamm? for a longer or shorter period. Some reptiles, some vipers for example, are viviparous, but none stand

als survive to this day which not only do not suckle their young,[17] but which lay eggs, the Ornithorhynchus and the Echidna, and in the Eocene there were a number of allied forms. They are the survivors of what wa

s mother, and "hands on" to its offspring. All the mammals, except for the two genera we have named, had already before the lower Eocene age arrived at this stage of pre-adult dependence and imitation. They were all more or less imitative in youth and capable of a certain modicum of education; they all, as a part of their development, received a certain amount of care and example and even direction from their mother. This is as true of the hy?na and rhinoceros as it is of the dog or man; the difference of educabili

by which the land vertebrates arose to predominance. The mudfish would have seemed then a poor refugee from the too crowded and aggressive life of the sea. But once lungs were launched into the world, every line of descent that had lungs went on improving them. So, too, in the upper Pal?ozoic, the fact that some of the Amphibia were losing their "amphibiousness" by a retardation of hatching of their eggs, would have appeared a mere response to the distressful dangers that threatened

the horse (Eohippus), tiny camels, pigs, early tapirs, early hedgehogs, monkeys and lemurs, opossums and carnivores. Now, all these were more or less ancestral to living forms, and all have brains relatively much smaller than their living representatives. There is, for instance, an early rhinoceros, Titanotherium, with a brain not one tenth the size of that of the existing rhinoceros. The latter is by no means a perfect type of the attentive and su

particular (Smilodon), a small fierce-looking creature with big knife-like canines, the first sabre-toothed tiger, which was to develop into greater things. American deposits in the Miocene display a great variety of camels, giraffe camels with long necks, gazelle camels, llamas, and true camels. North Ame

appear in northern Africa as snouted creatures; the

e we have as yet not a single bone. It was half ape, half monkey; it clambered about the trees and ran, and probably ran well, on its hind legs upon the ground. It was small-brained by

egrees a little more and a little more. And each year its summer point shifted a little further from perihelion round its path. These were small changes to happen to a one-inch ball, circling at a distance of 330 yards from a flaming sun nine feet across, in the course of a few million years. They were changes an immortal astronomer in Neptune, watching the earth from age to age, would have found almost imperceptible. But from the point of vie

erate time, and many of the warmth-loving plants and animals had gone. Then, r

s of years it receded, to advance again. Europe down to the Baltic shores, Britain down to the Thames, North America down to New England, and more centrally as far south as Ohio, lay for ages under the glaciers. Enormou

for example, which grew two or three thousand years ago, are found in Scotland at latitudes in which not even a stunted oak will grow at the present time. And it is amid

ut in the Time diagram on page 60 we follow H. F. Osborn in accepting

m of the Gl

p. 14. That diagram, if it were on the same scale as this one, would be between 41 and 410 fe

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