1034 HISTORICAL GEOLOGY. 



deteriorate when care ceases. But in wild nature variations are, in general, 

 the slow and sure result of the conditions — the organic conditions on 

 one side and the physical and biological on the other; they should occur, 

 generally, in a large part of the associated individuals of a species ; and 

 being Nature-made, the results are permanent. When, therefore, a variation 

 appears that admits of augmentation by continued interbreeding, progress 

 should be general ; and the unadaptable few should disappear, not the 

 '' multitudes." 



Under such a system of evolution, — evolution by regional progress, — 

 the causes of variation mentioned by Darwin are all real causes. But they 

 act directly, after the Lamarckian method, without dependence for success on 

 the principle of natural selection. Use and disuse, labor, strife, physical 

 changes or conditions, and organic influences act as such, and have their 

 direct effects. The plants that migrated in the Tertiary from the Arctic 

 regions southward over Japan and North America, and became new species 

 on the way, simply changed. That is the sum of knowledge on the subject. 



Man affords an example. The gradual gain of some races in lands and 

 supremacy, and the disappearance of the inferior races, is an example of the 

 Survival of the Fittest, or Natural Selection. But the superior races de- 

 rived the power which led to their survival and preeminent position through 

 favoring conditions in environments, that is, in geographical, geological, and 

 biological conditions and resources ; through the powers of endurance, the 

 courage, the mind power, the will power, which conflict with nature and with 

 other races of men in the world is fitted to develop ; and through the power 

 and self-assurance which comes of a high moral sense. Hence victory, sur- 

 vival. The survival of the fittest is a fact ; and the fact accounts in part 

 for the geographical distribution of the races of men now existing and still 

 in progress ; but not for the existence of the fittest, or for the jjower that 

 has determined survival. 



Natural selection, a means of determining the successive floras and faunas 

 of the world; a prominent cause of the geographical distribution of species. — 

 Natural selection is literally selection, survivals ; the survivors are those 

 that continue on to make faunas and floras. 



Independent derivation of allied species. — The existence of related 

 species under a genus or family on two or more continents, or in widely 

 distant regions, has brought up the question whether such occurrences are 

 not due in some cases to independent derivation. Migration accounts 

 unquestionably for a large part of them ; but it is doubtful whether it 

 accounts for all. If not for all, if the evolution has gone forward parallel- 

 wise on different continents, then organic law is not only the source of 

 change, the environments subordinate in influence, but the source of a 

 system of changes in the progressing evolution. The subordination to the 

 law of cephalization — that anterior concentration in the animal structure, 

 involving posterior abbreviation, attends progress in grade — accords with 

 this idea of organic control. 



