Editorial. 



That the rapid growth of special scientific nomenclatures is a 

 serious burden is felt by every scientific worker. Any effort, 

 accordingly, toward harmonizing conflicting usage should be and 

 is welcome. Not every such effort necessarily produces final 

 results, but if systematically pursued, it can hardly fail to elimi- 

 nate some confusion. In the work of the United States Geolog- 

 ical Survey decisions are constantly required of questions relating 

 to the naming and correlating of geologic formations. In many 

 instances the available evidence is so conflicting or so meager as 

 to preclude final judgment. Nevertheless, if geologic work is to 

 go on, and maps are to be made, a definite usage must in each 

 case be authorized. These decisions establish precedents, which 

 from time to time receive formal statement by the director and 

 become rules. Such a code, if we may borrow the legal term, 

 was published in the Teiith Annual Report of the Survey, and in 

 the Twenty-fourth Report is republished, revised, and enlarged by 

 the incorporation of the precedents established in the last thirteen 

 years, together with certain other changes recommended by the 

 committee charged with the revision. 



In the new rules there are many minor and some major 

 changes from the old. The action of the committee has been 

 conservative in some directions and radical in others. In part 

 the changes are seemingly retrogressive, though it is to be 

 remembered that a wise progression never hesitates to abandon a 

 position which experience has proved untenable. The return to 

 the use of "Tertiary," "Quaternary," "Triassic," and the adop- 

 tion of "Ordovician" as a systematic term, with the recognition 

 of the quadruple Lyellian divisions of the first-named are move- 

 ments which will bring the publications of the survey into closer 

 harmony with those of other organizations, and are fully war- 

 ranted by the developments of the last decade. The extension of 

 the criteria for the recognition of formations so as to include 



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