230 Proceedings of Boycd Society of Edinhurgli. [sess. 
the geologist is especially called upon to explain ; but I believe that 
among the causes which led to the differentiation of Man from his 
Tertiary congeners, this Ice age, with the concomitant alteration in 
climate, will he found to have been an important factor. The 
gradual interposition of such a huge mass of ice over a large portion 
of Europe — thus changing a subtropical climate to one of arctic 
severity — was followed by representatives of the flora and fauna of 
northern regions ; and it would appear that a wide zone in Central 
Europe became a common habitat for two distinct faunas — one 
hailing from the north and the other from the south. It is difflcult 
to account for the precise conditions which led to the intermingling 
of such different species as the mammoth, rhinoceros, Irish elk, 
cave-hear, cave-tiger, hyena, reindeer, hippopotamus, horse, &c. 
But whatever may have been the true explanation, whether ‘inter- 
glacial genial periods, or great extremes of temperature in the 
summers and winters, or any other cause, it is certain that a suc- 
cession, or successions, of such climatal alterations taxed the life- 
capacity and power of endurance of these animals to a degree which 
ultimately became unbearable, blow they are almost all gone from 
these localities. A number of them have become extinct, and 
others are still represented in more congenial climates, according as 
they possessed northern or southern proclivities. Man was the 
contemporary of them all, and he is the only conspicuous animal 
which successfully battled against these intensely adverse circum- 
stances. Man has emerged from this singular contest, still hearing 
traces of the means to which he resorted in the struggle for life. 
An upright posture, a manipulative hand, and a highly reflective 
brain are trophies of which he may he justly proud ; hut, like scars, 
they tell a tale of many battles. The history of these departed 
mammals, among which Man in his youthful days lived, moved, 
and had his being, throws much light on the ways and methods by 
which he accommodated himself to the exigencies of the climatal 
instability which obtained in Quaternary times. 
But, besides these common interests, the anthropologist is largely 
dependent on the geologist for explanatory details of the phenomena 
with which he has to deal, such as the position and chronological 
sequence of river gravels, sea beaches, aqueous deposits, peat beds, 
the formation and filling up of caves, &c., in all of which relics of 
