THE ERA' OF MAN. I 7 



of the earth is the quaternary epoch, or era of Civilization, 

 which in comparison ^yith the length of the four othei- 

 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 neptunic 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- 



VOL. II. c 



