598 T. C. CHAMBERLIN 



whether we should primarily seek a scale of reference and 

 nomenclature with a uniform arbitrary unit, as the meter or the 

 century, or whether we should strive to measure progress by its 

 inherent waves or nodes, or whether we should seek both 

 impartially. 



If the rhythmical view be the most laudable, effort should be 

 directed to the more complete and accurate determination of the 

 nature and limits of the periodicities, and to the modification of 

 present classification, so as to bring it into more complete con- 

 formity to these. If the uniformity view be the more laudable, 

 effort should be directed to reducing the adopted divisions to 

 quantitative equality by perfecting the geological column and 

 determining available scales of measurement, both stratigraphic 

 and chronologic. 



In either case, or in any other case which any individual geolo- 

 gist may prefer to put in the place of these selected ones, it is 

 necessary to push investigation a long way forward before an 

 International Congress can wisely give its sanction to any spe- 

 cific classification. 



Our shortest road to the great end sought will therefore be 

 found in promoting those investigations which will soonest give 

 the needed groundwork. Fortunately these investigations are 

 precisely those which best subserve the higher philosophic pur- 

 poses of the science. Two phases of this great work stand forth 

 prominently: (i) The systematic compilation and elaboration 

 of the great mass of data produced by studies in all parts of the 

 world, which are not now fully available, save to a few favored 

 workers connected with the great libraries, and to these only 

 through much labor duplicated in every individual case. It 

 will be admitted without discussion that the collocation and 

 organization of existing and forthcoming data would greatly 

 stimulate accretions and promote the end sought. (2) The 

 development of additional criteria of correlation. A preeminently 

 essential step in the progress of classification and interpretation is an 

 increase in the precision and the certainty of correlation of formations 

 in zvidely separated regions. 



