THE 



JOURNAL OF GEOLOGY 



MAY-JUNE, 1898 



A SYMPOSIUM ON THE CLASSIFICATION AND 

 NOMENCLATURE OF GEOLOGIC TIME- 

 DIVISIONS. 



The infelicities which arise from the uncertain use of terms 

 in the discussion of geologic time-divisions are more or less 

 fully appreciated by every working geologist. The peculiar dif- 

 ficulties which the varying and often inconsistent use of terms 

 imposes upon the student of geology when he leaves the narrow 

 confines of his text-book and tries to use the current literature 

 of the science, can only be realized by those teachers who have 

 encouraged this broader method of study and conscientiously 

 feel responsible for the results. Not every text-book, even, is 

 consistent with itself. It is too much to insist that it should be 

 consistent with general usage until a consistent general usage is 

 established. The importance of a more systematic classification 

 of time-divisions and rock-series has been recognized by the 

 international congresses of the last two decades. The limited 

 results that have been reached by the efforts of these congresses 

 seem to indicate that the problem must be worked out by gradual 

 approaches through tentative efforts. It perhaps also indicates 

 that the problem must be in large part worked out in the great 

 provinces or in the individual continents separately as a pre- 

 liminary to intercontinental coordination. Not a few geologists 

 who heartily sympathize with the effort to secure more uniform 

 and better practice are yet quite unwilling to have a rigid system 

 imposed by the vote of a body of so uncertain composition as 

 Vol. VI, No. 4. 333 



