198 The Field of Geoloyy—McGee. 



by Araerican geologists so exhaustively as apparently to leave 

 little for their successors in this field; but the indirect effects of 

 aerial circulation upon geologic phenomena produced through cli- 

 mate, oceanic currents, etc., affords a fit field for further study. 



Science never lifted the veil of the unknow^n upon more en- 

 chanting vision than when she vivified the fossils entombed in the 

 rocks and thus opened a vivid panorama of the earth's life stages, 

 stretching from the present back through unreckoned ag<^s to the 

 infancy of the organic world; and though paleontology has revo- 

 lutionized cosmology within two generations, its field is fertile as 

 ever and responds abundantly to intelligent cultivation. The in- 

 fluence of physical environ^nenf; upon the organism has been care- 

 fully examined, and an essential factor in the development of life 

 has thereby been brought to light; but, although the coals, lime- 

 stones, hydrocarbons, etc., have been separately studied, the general 

 reciprocal influence of the organism upon the physical environ- 

 ment, and thus upon the general process of differentiation of the 

 external shell of the earth, has never been comprehensively investi- 

 gated. This will eventually prove one of the most fruitful fields 

 of geologic research. 



Recurring now to the first principal category of processes, 

 viz., deformation, the most interesting and one of the most ex- 

 tensive of the partially explored fields of geologic research is found. 

 The structure of mountains has long been attentively regarded, 

 and many profound speculations concerning their origin have been 

 indulged in; and the origin of continents and ocean basins has 

 been considered by every student of the general geologic history 

 of the globe. Here the domain of the physicist and astronomer 

 on the one hand and that of the geologist on the other, overlap; 

 and the ablest minds of the generation have sought to solve the 

 problems presented by the phenomena. Here the physicist con- 

 tributes principles and makes deductions of great suggestiveness 

 and often of high value to the geologist; and here the geologist is 

 an agnostic, assails the deductions of the physicist, and, too fre- 

 quently for the good repute of physical science as applied to geo- 

 logic research, breaks them down. But the geologist is equally an 

 agnostic with respect to his own conclusions of higher rank than 

 mere generalizations; and he assails every inference of his fellows, 

 and unless he be rash indeed, guards his own course at every step 

 and feels his way cautiously through the tangled maze of ambigii- 



