Presidential Address. 
227 
physical peculiarities can be separately evolved, manifestations of 
culture as expressed by manufacture and art cannot evolve on lines 
absolutely similar. If these lines are found to be alike in two or more 
separate regions, then it is safe to conclude that they are the expressions 
of the mental development of one race only. 
LiTHOLOGICAL DIVISIONS. 
Let us recapitulate the ten divisions, or lithological epochs, defined, 
as previously stated, by the character of the stone or bone imple- 
ments discovered at different geological levels, and with which occur, 
as often as not, remains of animals that are either extinct, or of 
others that still survive although in sparse numbers, and lastly, of 
those which again form the animal fauna of to-day. Of these ten 
divisions it will be safer, for the present at any rate, to drop the three 
most ancient and little-accepted periods, namely, the Icenian, the 
Messinian, and the Strepvan, leaving thus, in the ascending scale, seven, 
namely : the Chellean and the Acheulean, forming the Lower Palaeolithic ; 
the Mousterian, forming the Middle Palaeolithic, and the Aurignacian, 
Solutrean, Magdalenian, included in the Upper Palaeolithic. Lastly, 
there is the Azilian, certainly a phase of transition that may or may not 
be included in the Neohthic. 
If we assume that the deductions from the history of the Great Ice 
Age are correct, this Azilian division would extend into "Post Glacial" 
times, and may bridge the Palaeolithic and Neolithic periods. At the 
other (earlier) end the Chellean and Acheulean culture evolved during the 
Middle Interglacial epoch, and are followed by the Mousterian during 
the Second Glacial episode, which in turn is, in all probability, replaced 
by the Aurignacian epoch, the^age or duration of which lasts wholly within 
the Last Interglacial period, giving Vay to the Magdalenian, the phase 
of which extends to the very end of the Pleistocene, the Azilian, as said 
previously, replacing the Magdalenian. These divisions of the Ice Age, 
based as they are on geological facts, are worthy of acceptance. Unfortu- 
nately, they do not apply to South and Central Africa, where, it is 
now safe to say, no traces of such glaciation exist. The climate here, 
during these Ice periods, was not affected thereby, and it may be taken 
for granted that during the Pleistocene, it remained the same as it is 
to-day. 
But the artefacts themselves, so abundant in our river gravels and 
elsewhere, their style, their possible contemporaneity with remains of 
Mastodon, and with certainty with two extinct Antelopes, much more 
ancient animals than those with which they have been associated in 
Europe, must make us accept the possibility — for in prehistoric studies 
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