Jan., 11)1 < J The Future For Geologists 95 



sciences and the social sciences, it calls for some knowledge 

 of Anthropology, Ethnology, Archeology, and even Modern 

 Psychology. With all these contacts what then is the geog- 

 rapher to do? In brief, he is to work out the actual relations 

 existing between man, and his environment, whether profitable 

 or adverse; find geographic reasons, so far as they exist, for 

 man's distribution, occupations, migrations, diseases, beliefs, 

 and culture, not only in the present, but in the past. And, as his 

 work progresses, he should be able to forecast for man, and 

 advise ; to show how man can succeed better or fail less by more 

 careful adjustments to the environment ; to show what we are 

 doing here that we should not do here, but should do elsewhere; 

 to show the possibilities of new lands and even of old ones, and a 

 multitude of other things, for the good of his race. Geography 

 holds many attractive openings for the geologist of the future 

 and hence deserves probably the mention accorded it here, 

 although it is not itself a branch of Geology. 



11. It remains now to look into the field of cosmic geology. 

 We are in a transition stage from rather secure trust in the 

 Laplacian Hypothesis for the origin of the Earth and its 

 associates, to a rather wholesome distrust of this theory and a 

 chary approach to the Planetesimal Hypothesis. The old is 

 decidedly unsatisfactory. The new is not wholly acceptable, 

 but is a very suggestive working scheme. It is necessary for 

 Geologists everywhere to adjust their thinking and interpreta- 

 tions to the new theory and to test them out together. Some 

 weak places are found in the theory, but I am not here to discuss 

 them. Let me mention, however, that it does not seem to 

 account for the free oxygen in the air, and it leaves us to suppose 

 that the chlorine in the salt of the sea came from the igneous 

 rocks. I have made a little calculation on the latter point, a 

 summary of which may prove interesting. Analyses show 

 that chlorine occurs in igneous rocks to the value of about .06%. 

 In the sea common salt constitutes about 77% of the salts and 

 chlorine at least half of all dissolved mineral matter. The 

 calculation shows that if a layer of igneous rocks twenty miles 

 thick all over the earth, or seventy-five miles thick over the 

 continents should be disintegrated, the process would liberate 

 about as much chlorine as is now in the sea. But if this amount 

 of igneous rock had disintegrated, where is the waste other than 

 the chlorine? Sedimentary rocks, as formerly stated, would 



