may be mentioned the five-toed and four-toed ancestral horses, the trunkless and small-tusked ancestral elephant, the cat-like forerunner of the modern seal. At that time, too, we find the first record of a primate, that order of mammals to which the zoologists refer man. This was evidently a small quadruped with toes terminated neither in hoofs nor claws, but with rather horny nails, and with teeth adapted neither for grinding grain like those of a horse nor for tearing flesh like those of a tiger nor for gnawing nuts like those of a squirrel, but like those of a man for eating herbs, fruits and eggs. But in general appearance this creature resembled a rat much more closely than a monkey, ape or man. Bones of that lowly type of primate have been found in North America, Asia and North Africa.
Somewhat higher in the series of Cenozoic strata of India, there were recently found a fragment of jaw which had teeth totally different from those of any nonprimate, somewhat different from those of a monkey, and closely resembling those of the great apes and of man. That animal lived somewhere between 2,000,000 and 10,000,000 years ago. He is believed to have been ancestral to the apes, chimpanzees, gorillas and mankind, all of which had by that time become completely differentiated from the monkey strain. If that be true, man has become distinct from the other anthropoids since that creature left his bones on the banks of an Indian stream. Narrowing our attention now to the strain that leads to man, the next fossil of significant interest is that known as the ape-man of Java. Some thirty years or so ago there was found on the island of Java a partially cemented layer of gravel and sand containing fossil bones and fossil plant remains. The plants were of the same sort as found elsewhere in rocks known to have been formed rather late in the Cenozoic era just before the first glaciers of the great ice age were accumulating, therefore, it must be that the associated animal bones are also of that age.
The skull of this animal had brain capacity somewhat greater than that of the most brainy apes now living and somewhat less than that of the smallest-brained human tribe. He had a receding forehead and a heavy ridge of bone above his eyes like an adult chimpanzee; yet his leg-bones show unmistakably that he stood and walked erect upon his hind limbs. The name ape-man describes him exactly; he was truly intermediate in body structure between the apes and man. He lived 1,000,000 or 2,000,000 years ago. In rocks of just about that same age in England there have been found crudely fashioned flint implements, unnistakably shaped by some intelligent creature with hands so developed as to be capable of holding a stone and striking it with another stone. Modern apes have been observed to hold clubs in their clumsy hands, but none of them can at will touch his thumb against the tip of each finger on the same hand. Presumably the creature who chipped the flints found in those rocks near Foxhal, England, could do so.
Then came the first of the great glacial advances of the ice age about 1,000,000 years ago. Five times the northern lands were buried beneath a mantel of moving ice. Five times the ice melted until the glaciers were at least as small as those now remaining on Greenland and in the valleys of Alaska. In the gravels deposited in Germany by the rivers flowing from the melting ice of either the first or the second of these interglacial intervals, there has been found the jaw of the so-called Heidelberg man. The jaw resembles that of a modern man; its sides are nearly parallel, the canine teeth are only a little higher than the incisors and molars. But it has no chin at all, and the portion of the jawbone which articulates with the skull just in front of the ears looks considerably like the equivalent portion of an ape's jaw. Scientists classify that creature as a member of the same genus to which modern man belongs, but as a different species.
Gravels of later interglacial stages have revealed the bones of still
