NOMENCLATURE OF THE OHIO FORMATIONS 539 



and Dundee limestones of Michigan.^ In 1894, however, Mr, 

 Darton named and described the Monroe shales, a Devonian for- 

 mation of southeastern New York,^ and on this account there 

 was some uncertainty whether the Michigan name would be 

 retained or not. The question was submitted to Mr. Bailey 

 Willis, chairman of the Committee on Geologic Names of the 

 U. S. Geological Survey, who has sent me the following answer : 



The Committee on Geologic Names on May 12 took action on the valid- 

 ity of the term Monroe in several publications of 1891, 1892 [1893], and 

 1895, as the name of a group of rocks distinguished in southern Michigan, as 

 against the standing of the name published in 1894 for a shale formation in 

 southeastern New York. 



The committee recommended that the Monroe group of southern Michigan 

 should retain the name, and this action has been approved for official publi- 

 cations of the Geological Survey. 



The conclusion was reached on the ground that priority and prescription, 

 or established usage, are combined in the Michigan application of the term 

 in such a way as to make its continued use more desirable than that of 

 Monroe shale in New York ; but the case was not considered one in which 

 priority was so definitely obvious as to justify the conclusion on the ground 

 of the publication of 1891-2 [1893] only, since in that publication the defi- 

 nition was inadequate.3 



In 1898 Professor Grabau proposed the name "Greenfield 

 limestone" for the Ohio Waterlime, from the town of that 

 name in the northeastern corner of Highland county, in south- 

 ern Ohio, where the limestone is well shown and extensively 

 quarried. '^ This is certainly an appropriate name for the forma- 

 tion in central and southern Ohio, which will be available in case 

 further study shows that " Monroe " is not a suitable name for 

 the Waterlime in this section of the state. 



It is to be remembered, however, that Dr. Orton published 

 the name " Greenfield Stone " in 1871 in a chart of the " Geologi- 

 cal Series of Highland County ;" s but did not use it as a forma- 

 tion name, since he described it under the name of " Helder- 

 berg limestone."^ 



' Geol. Surv. Mick., Vol. V, Part II, pp. 26-8. 



""Bull. Geol. Soc. Ainer., Vol. V (March, 1894), p. 374. 



3 Letter of May 18, 1903. s Geol. Surv. Ohio, Rept. Prog, hi 1S70. 



"^ Science, N. S., Vol. VIII, p. 800. ^ Ibid., pp. 287-94. 



