H.—ANTHROPOLOGY 133 
made by two distinct generaofmen. Quite lately, however, Prof. P. G. H. 
Boswell, under the guidance of Dr. Leakey, has examined the geological 
formations in the region where the discoveries were said to have been 
made, and he is now convinced that there is no proof of the association 
which has been claimed. The human remains in question seem to have 
been obtained from disturbed deposits, and may have been buried at a 
comparatively recent date. With later types of stone implements and 
remains of modern mammals, the only satisfactory fragments of the 
human skeleton which have hitherto been found in Africa belong to the 
genus Homo. Many of the fossil forms are related to the surviving 
South African bushman, and if any of these passed directly from northern 
Africa into Spain, as has sometimes been supposed, they must already 
have learned to make rafts by which they could cross the Straits of 
Gibraltar. 
The only fossil hitherto discovered in Africa, which suggests that that 
continent may have produced man, is the immature skull from a deposit 
of uncertain age (probably Pleistocene) at Taungs in Bechuanaland, which 
was named Australopithecus by Prof. Raymond A. Dart in 1925. It 
belongs to an ape, and seems to exhibit more human characters than the 
skull of any of the existing apes; but Prof. Dart’s complete account of 
the fossil has unfortunately not yet been published. 
The earliest known jaw of an ape, Propliopithecus, was discovered long 
ago in the Oligocene of Egypt, and numerous jaws of apes related to the 
existing chimpanzee are now being found in the Miocene of south-east 
Africa. Equally abundant, however, are the jaws of apes in the Mio- 
Pliocene deposits of northern India, and some of the teeth preserved in 
- them exhibit a remarkable approach to those of man. I still think, indeed, 
that according to our present knowledge the links which connected apes 
with man are most likely to be found in south-central Asia. As the late 
Joseph Barrell pointed out, the east to west ridge of the Himalayan 
Mountains was gradually raised up at the time when northern India was 
covered with a great forest which swarmed with apes of many kinds. 
The formation of the ridge separated off a northern portion of the forest 
which became subject to comparatively inclement conditions. The apes 
stranded in this northern portion would be disturbed by the extensive 
destruction of the trees, and the survivors would be driven to be ground- 
apes and change their habits of feeding. They would thus be modified 
in the direction of man. Regarded from the zoological point of view, of 
course, man is an arboreal mammal which has left the forest. His remote 
ancestors, by continuing to live in the forest, preserved their jaws, teeth, 
and limbs nearly on the primitive mammalian plan, while the brain alone 
made progress ; and, as Dr. H. S. Harrison has remarked, if there had 
been no trees during the Tertiary era, man would probably not have 
appeared in his present form. 
These considerations, with the geographical distribution of the few 
oldest known remains of fossil man, led the late Dr. Davidson Black to 
make plans for a systematic examination of the later Tertiary deposits of 
south-central Asia. In 1925 he reviewed the whole subject in an im- 
portant paper published by the Geological Society of China. In the 
