The Galena and Ma<iuoketa Series. — Sardeson. 335 
a siitiilar change. In short, the liberty has been taken to change 
the names of geologic formations because the fossil after which 
the names were given, have been placed in a new genus or 
in new genera. Thus Stictopora bed has become Rhininidictya^ 
bed, Orthisina bed has been changed to Clitambohites bed, 
and it is proposed to reject the name Camarella bed. It would 
be necessary not to name geologic formations after geologic 
type fossils if the name of the formation must change as often 
as the fossil is reclassified. A name once given should not be 
changed, or at least must not be subject to varying and contin- 
ued change as such license would necessitate. The chief source 
of confusion comes, however, from discordant correlation. 
Unless uniformity in classification can be maintained 
throughout a continuous area, in neighboring counties and in 
adjoining states, there will be little use in attempting exact 
correlation with distant areas,-and thus also, unless uniform- 
ity in nomenclature can be locally established the introduc- 
tion of names from distant correlated formations can be of 
little use and possibl}" ^^y he very obstructive. I have there- 
fore proposed both to classify the Ordovician uniformly and 
exactly over the entire area in the manner that accords best 
with the nature of the formations, and, to preserve a system 
of nomenclature that will be free from confusion of terms due 
to attempted correlations with other areas. I would indicate 
the correlated formation by additional names, as Galena 
(Trenton) formation or Trenton (Galena) formation, as in the 
accompanying diagram, in which I have combined the local 
classification for our area, with Winchell and Ulrich's corre- 
lation. In such a scheme the nomenclature can be changed by 
shifting the terms Utica, Trenton, etc., without confusing the 
classification. Ultimately it may be that the names Galena 
series and Maquoketa series will be no longer of use; that is. 
the correlation may become exact instead of approximate. To 
be sure, authors liave applied the name Trenton, etc., as if 
there were no doubt as to the exact equivalency, but not only 
have the same authors failed to use the same names in neigh- 
boring counties and states consistently, but also even in the 
same place authors vary in their application of them. 
For more than fifty years geologists have attempted to ap- 
ply the names "Trenton" and "Hudson River," in this area 
