942 GEOLOGY 



Man's control has not thus far been characterized by much 

 recognition of the complicated interrelations of organisms and of 

 the consequences of disturbing the balance in the organic kingdom, 

 and he is reaping, and is certain to reap more abundantly, the 

 unfortunate fruits of ignorant and careless action. For the 

 greater part, man has been guided by immediate considerations, 

 and even these not always controlled by much intelligence. Thus 

 great wantonness has attended his destruction of both plant and 

 animal life. But a more intelligent as well as a more sympathetic 

 attitude is developing, and will doubtless soon become dominant. 

 A new era in control and in evolutionary selection is dawning. 

 New varieties and races are being produced that not only depart 

 widely from the parent stock, but diverge in lines chosen to meet 

 given conditions, or to produce desired products. How far this 

 may yet go it is impossible now to predict. 



Prognostic Geology. The long perspective of the past should 

 afford at least some suggestions of the future, but it must be con- 

 fessed that the most important conjectures as to the future are 

 dependent on interpretations of the past that are not yet certain. 

 A word has been said relative to a possible return of a glacial 

 epoch, but no sure prediction can be made. Question has been 

 raised as to whether the deformations of recent times are over, but 

 the answer remains uncertain. The duration of the earth as a 

 habitable globe has been a common theme of prognosis. A final 

 refrigeration as the result of the secular cooling of a once molten 

 globe has been the usual forecast, and the final doom of the race 

 has been a favorite theme for pseudo-scientific romances. But 

 this all hangs on the doctrine of a former molten earth, if not on 

 the doctrine of its origin from a gaseous nebula. Under the alter- 

 native conception of a slow-grown earth conserving its energio, 

 conjoined with a more generous conception of the energies resident 

 in the sun and the stellar system, no narrow limit need be assigned 

 to the habitability of the earth. A Psychozoic era, as long as the 

 Cenozoic or the Paleozoic, or an eon as long as the cosmic and the 

 biotic ones, may quite as well be predicted as anything less. The 

 forecast is at best speculative, but an optimistic outlook seem- 

 more likely to prove true than a pessimistic one. An immeasurably 



