Jan., lUlTj The Future For Geologists 85 



a larger scale for more refined areal geology than can be done on 

 the smaller scales. 



2. In the field of areal geology — mapping by means of 

 colors or designs the distribution of the rocks of each age or 

 kind ^thc present time finds relatively little territory covered. 

 In the United States about 200 folios have been published. 

 Each covers from one to sixteen of the one inch to the mile 

 sheets, or in all, about 850 quadrangles, or nearly 200, 000 

 square miles. At the present rate of progress our countrv will 

 last the Federal survey nearly 500 years. It may be said, 

 however, that a good deal of work has been done by State 

 surveys of about the same quality, some even better, and that 

 this time may be cut down one-half. The countries of Europe 

 are not as a whole far in advance of the United States, and most 

 of the rest of the world has not been disturbed by any such 

 refined work. 



Mapping on the scale of one mile to the inch does not call for 

 careful enough field work to even open many of the problems of 

 geology. Some of our State surveys, some private companies, 

 and occasional parties in the Federal survey have undertaken 

 local studies of a much more detailed nature than the general 

 run of work on the above scale. For example, see Butte, 

 Montana, and Bisbee, Arizona, regions. 



Geologists have made many generalizations and have built 

 up many working hypotheses for all kinds of purposes. Of 

 course, the work in the field upon which they are built has not 

 yet gone far enough to thoroughly test the validity or falsity 

 of either the generalizations or the hypotheses. Not until 

 the evidence is all in can we say the laws are known. Better 

 working hypotheses and more reliable statements of principles 

 are appearing every year in the various fields of geology, while 

 the older theories and statements having served their day 

 as stepping stones are cast aside. Even in the mapping of 

 areal geology and the interpretations thereof, the field is almost 

 infinite, if the whole world be taken into account, and the scale 

 be large enough to show what details can really be seen. 



3. In the field of stratigraphy and stratigraphic interpreta- 

 tion the Geologist uses the areal work just discussed and 

 attempts to unravel the succession of events — the chronology 

 of geology. It is by this means in part that he has been able to 

 assign units of time to his geologic history of the earth. Breaks 



