ABSTRACT
So far as the surface of the earth is concerned, great parts of it have been worked over in minute detail for long periods of time, in some cases for periods stretching back beyond the confines of human history. Year by year, an increasing part of the earth’s surface is being brought within the scope of man’s civilization. There is perhaps no more wonderful thought connected with an old and developed country like England, or France, or China, than the reflection that almost every acre of it has been in some way scraped, or pared, or cultivated, or mined, or drained, or built upon. Here and there one may find a small spot which has remained undisturbed for a generation or more, but even that has probably been subjected to cultivation or alteration at some not very remote period.
