230 CHARLES S. PROSSER 



geology to the Director of the United States Survey and Geolo- 

 gist in charge of Areal Geology, to whom these questions in 

 nomenclature are referred : 



The survey distinctly recognizes the right of priority, that is to say, the 

 name first applied to a well defined geologic unit is to be preferred. The 

 qualifying conditions, on account of which the name maybe rejected and one 

 of later application used, are (i) that the name has been previously applied 

 to some other unit, and (2) that the unit to which the name was applied was 

 not well defined. 



Thus, in the case which you cite, the term Waverly conglomerate 

 (Andrews) would not hold if Waverly had previously been used for some- 

 thing else, and by application of the same rule Waverly series should be dis- 

 carded if Waverly conglomerate had priority. The Logan group (Orton) 

 should not stand as opposed to Logan sandstone. 



In these questions there is often a personal element which makes it a 

 matter of regret that some desirable name should not be adopted, but we feel 

 that the advantages of clearness and definition in science must be superior to 

 such conditions, and that the rule should be rigidly applied. 1 



Dr. George H. Girty, of the United States Geological Survey, 

 who has been engaged for several years in a thorough study of 

 the stratigraphy and paleontology of the Waverly series in Ohio, 

 Michigan, and Pennsylvania, concurs in regarding the upper part 

 of the series in central Ohio as composed of two formations, as 

 may be seen from the following quotation : 



I have seen the Logan group at Logan and vicinity and also at various 

 points in Licking county. I quite concur with you in regard to the separate- 

 riess of the two component members in central Ohio at least, and am in 

 uncertainty as to the reasons which led Professor Orton to unite the two beds 

 under a common name. 2 



The lower part of this formation is well shown in the Vogel- 

 meier and Havens quarries, where Conglomerate II is succeeded 

 by from 4^ to 6 feet of greenish-gray to bluish argillaceous 

 shales, and these are followed by from 11 to 17 feet of quite 

 massive buff sandstones, capped by alternating shales and sand- 

 stones, 183^ feet of which are shown at the top of the Vogel- 

 meier quarry. There are fair exposures of the remaining part of 

 the formation in "the gorge" to the east of the Havens quarry, 



1 Letter of December 18, 1900. 2 Letter of January 5, 1901. 



