294 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1925 



adjustment to the new foods, and the institution in their herds of a 

 discipline, subordination, and leadership which are almost tribal. 

 These last qualities were rendered doubly necessary by the consequent 

 rapid development of carnivora, and the need for scrapping passive 

 and even active means of defense in order to secure the power, speed, 

 and reserve necessarv to follow their food harvests over great 

 stretches of country. At the same time the habits and instincts thus 

 brought about were those which man, by domestication, has been able 

 to turn to liis own ends. Thus at a blow, as the outcome of this stage 

 of Tertiary evolution, there became available for mankind not only 

 his chief plant food and drink, his luxuries as well as his necessaries, 

 but his chief animal foods, together with his aid from the speed, 

 strength, service, and endurance of tlic animals which he domesti- 

 cated, and to which he assumed the position of leader of the herd. 



But while with the aid just described it was possible for mankind 

 to progress far on the road of civilization, progress would have been 

 stopped, and as a matter of fact was seriously retarded, u.ntil the 

 discovery and utilization of the solar energy stored up in the earth's 

 crust during the Carboniferous and subsequent Periods in the form 

 of coal and other fossil fuels. The very exceptional conditions, cli- 

 matal, geographical, and botanical, requisite for coal formation, oc- 

 curred all too seldom in geological history, but it has so happened 

 that few areas of the earth are devoid of coal belonging to one Period 

 or another; and the shaping of kingdoms and dominions, has been 

 such as to include supi)lies of fuel in most of them. 



Whatever may be the main sources of energy in the future, radiant, 

 intratelluric, hydraulic, tidal, atomic, we have been largely depend- 

 ent in the past, and probably shall continue to depend for many 

 years to come, on that poi"tion of the solar energy stored up by 

 vegetation, and especially on that preserved in the earth crust in 

 the form of coal. 



But again civilization must have been greatly hampered or driven 

 into a different course but for the agencies which have sorted out 

 from the medley of materials of which the earth is composed, simple 

 compounds or aggregates of compounds, or in rarer cases simple 

 elements, in such a form that they are available for human use 

 without the expenditure on them of excessive quantities of energy. 

 The concentration of metalliferous ores, salines, and the host of 

 other mineral resources has made perhaps the most important con- 

 tribution of all to the latest stage — in good and evil — attained by 

 civilization. 



Finally, doubt may be expressed whether man could have attained 

 his present position if he had not made his appearance compara- 

 tively soon after a period of intense earth activity, when broad areas 



