THE HUMAN OR PRESENT PERIOD 939 



There are areas in the Orient, once well settled, where nothing 

 grows except such plants as find a foothold in the crevices of the 

 rock. Soils with sandy subsoils have been washed away, leaving 

 barren wastes, and the sands derived from the denuded subsoil 

 have been driven by the winds over adjacent fertile tracts, and by 

 burial have included them in the common waste. The explanation 

 of much of the former richness and present poverty of Oriental 

 peoples no doubt lies in this simple process. This impoverishment 

 of soil threatens many peoples to-day, and is in process of actual 

 realization. 



Glaciated lands are comparatively new fields for civilization, 

 and the soil-factor there has a character quite its own. 1. Near 

 the centers of glacial radiation, the old soils were borne away, and 

 new soils have not always developed in equal amount in their stead. 

 A reduced fertility is the result. The half -decayed rock below 

 was largely worn away, and a long period must ensue before a new 

 soil will have become effective. These areas lie chiefly in high 

 latitudes where other factors do not favor human development. 

 2. In regions of glacial deposition, which fortunately include the 

 greater and the more southerly parts of the glaciated area, a deep 

 sheet of comminuted rock-material, ready for easy conversion into 

 soil by weathering and organic action, covers great plains, and has 

 a gentle relief that aids in restraining its removal. In the periph- 

 eral belt of the glaciated area in North America, for a width of 400 

 or 500 miles, the subsoil of glacial flour and old soil, glacially mixed, 

 has an average thickness of about 100 feet. A similar statement 

 may be made of a large area in north-central Europe. The average 

 thickness of the residuary soils of unglaciated regions similarly 

 situated is about 5 feet. The twenty-fold provision for permanent 

 fertility thus arising from glaciation seems likely to be a factor of 

 importance in the localization of the basal industry of mankind, and 

 of the phases of civilization that are dependent on it. 



With the evolution of the industrial arts, resources which were 

 neglected at first have come to play important parts in the distri- 

 bution and in the activities of the race, among which are the long 

 and growing lists of mineral resources. Chief among these are the 

 metallic ores, the fossil fuels v the mineral fertilizers, and the struc- 



