THE ERA OF MAN, 17 
of the earth is the quaternary epoch, or era of Civilization, 
which in comparison with the length of the four other 
epochs almost vanishes into nothing, though with a comi- 
cal conceit we usually call its record the “history of the 
world.” As the period is characterized by the development of 
Man and his Culture, which has influenced the organic world 
more powerfully and with greater transforming effect than 
have all previous conditions, it may also be called the era 
of Man, the anthropolithic or anthropozoic period. It might 
also be called the era of Cultivated Forests, or Gardens, 
because even at the lowest stage of human civilization 
man’s influence is already perceptible in the utilization of 
forests and their products, and therefore also in the 
physiognomy of, the landscape. The commencement of 
this era, which extends down to the present time, is 
geologically bounded by the end of the pliocene stratifica- 
tion. 
The neptunice strata which have been deposited during 
the comparatively short quaternary epoch are very different 
in different parts of the earth, but they are mostly of very 
slight thickness. They are reduced to two “systems,” the 
older of which is designated the diluvial, or pleistocene, 
and the later the alluvial, or recent. The diluvial system 
is again divided into two “formations,” the older glacial and 
the more recent post glacial formations. For during the 
older diluvial period there occurred that extremely remark- 
able decrease of the temperature of the earth which led to 
an extensive glaciation of the temperate zones. The great 
importance which this “ice” or “glacial period” has exer- 
cised on the geographical and topographical distribution of 
organisms has already been explained in the preceding chap- 
19 
