442 CHARLES S. PROSSER 



it appears to the writer that the name Sandusky limestone ought to 

 be dropped. If it were now applied to the lower formation, it would 

 cause serious confusion, since that was named at the same time the 

 Columbus limestone, under which designation it is well known in 

 geological literature. It is to be noted that in Dr. Newberry's classi- 

 fication and definition of these two limestones the name "Sandusky" 

 appeared first, but on the same page as that of Columbus. 1 It is 

 thought, however, that the above decision is in accordance with Rule 

 7 of the United States Geological Survey regarding "Nomenclature 

 and Classification," which states that "in the application of names 

 to members, formations, and larger aggregates of strata, the law of 

 priority shall generally be observed, but a name that has become 

 well established in use shall not be displaced by a term not well known 

 merely on account of priority." 2 "Delaware limestone," published 

 by Dr. Orton in 1878, is the next name applied to the upper division 

 of the Devonian limestones of Ohio, and this is now adopted for this 

 formation. In my paper on "The Nomenclature of the Ohio Geo- 

 logical Formations," published in the Journal of Geology in 1903, 3 

 "Sandusky limestone" was used for the upper formation of the 

 Devonian limestones, because, as there stated, it antedated "Delaware 

 limestone" by five years, and the error in correlation between the 

 limestones of Sandusky and Delaware was not known to the writer. 

 The thickness of the Delaware limestone in the Sandusky region, 

 according to Dr. Swartz, is between forty and fifty feet, which is 

 greater than that in central Ohio. 



1 Loc. cit. 



2 Twenty-fourth Annual Report of the Director of the U. S. Geological Survey 

 (1903), p. 24. 



3 Vol. XI, p. 519, and see pp. 521 and 537. 



