EXTINCT APES 289 



that are completely masked by the ordinary geological diagram, 

 such as that used by Sutcliffe in the same discussion. 



Now what bearing have these facts of simian paleontology 

 upon the vital question of the antiquity of the man-tribe ? There 

 is no indubitable inference, but there are certain probabilities. 

 We know that by the Middle Miocene there had been time for 

 one branch of the gibbonoid stem to grow far out in the direction 

 of the chimpanzee. We suppose that man's latest arboreal 

 ancestor was a somewhat gibbon-like creature, more intelligent, 

 with shorter arms, and probably larger than the living gibbons. 

 Such an animal may well have been contemporary with Dryopi- 

 thecus. Or are we to believe that the branch which had so much 

 the farther to grow, was also much the later to originate? It 

 may be so. It is not inconceivable that those first expeditions 

 to the ground, which were so pregnant with destiny, were not 

 carried out until the Late Pliocene. But if that be so, there was 

 a long pause in the upward evolution towards man : through 

 the long ages of the Middle and Upper Miocene and the Lower 

 Pliocene everything was ripe for the advent of the man-tribe, 

 and yet none appeared. 



Whatever weight attaches to the negative evidence — the fact 

 that no remains of the Hominidae have been found in the Lower 

 Pliocene or in the Miocene — tells in favour of this view. But 

 negative evidence is of course notoriously inconclusive in geology, 

 and the possible proofs would be limited to bones, if so be that 

 the ground-dwellers were slow in learning to chip stones with 

 sufficient cunning to make their artificial character recognisable. 



However this may be, the lesson of simian paleontology is 

 clear. If there were no Hominidae in the Late Miocene, our 

 ancestors tarried strangely long in the trees. 



