Editorial Comment. 319 
printed pages that have been devoted to these terranes ; but 
which, in too manj^ cases, is left wholly screened under the 
vagueness of presentation, or is left to be adjusted by some 
later investigator, who, not being familiar with the locality 
nor with the precise scope of the terms already employed, 
doubles the difficulty b}^ duplication or division. There is, 
therefore, no legitimate recourse open to the present genera- 
tion of geologists but to resort to the "law of priority" in 
the selection of terms for stratigraphic divisions, and to rele- 
gate to synom^^niy all later terms applied to the same forma- 
tions, so soon as it is sufficiently demonstrated that the form- 
ation named in the two countries, or in neighboring states, 
reall}' is the same. 
There is, of course, one other method to be pursued, a prac- 
tice that is introduced into the United States by the United 
States Geological Survey, viz. : begin de novo, re-examine and 
remap all the formations previously mapped and named, and 
apply to them new terras, ignoring all previous designations. 
That may be justifiable on the part of a grand national sur- 
vey, from some points of view, but from others it is not. In- 
deed, it is quite unjustifiable and unjust, from the historical 
point of view, and also will serve in the distant future to 
breed still greater confusion and discord; for. however great 
the present authority with which results are reached and 
names applied to the formations, the future will certainly fur- 
nish a greater and a more exact science, and our present 
labors will be considered juvenile in comparison with those, 
and will perhaps be swept into the waste-basket with as little 
compunction as we so treat the labors of our own predeces- 
sors. Therefore geological nomenclature cannot be consid- 
ered stable, except momentarily, unless it be based, as already 
stated, on the law of priovittj, same as in the biological sci- 
ences. 
This basis of nomenclature Prof. Renevier has adopted, 
and that gives to his scheme a standing value and durability 
which will commend it for many years to all geologists. 
Unfortunately one geologist cannot compass fully the liter- 
ature, and judge of the value of all the contributions from 
all parts of the world. The author of this paper therefore 
advised with many European fellow-geologists, and it ma}' be 
