142 H. S. WILLIAMS — NOMENCLATURE AND CLASSIFICATION 



Dh Hampshire formations ....... Catskill. 



Dj Jennings formations Chemung. 



Dr Romney shale Hamilton. 



M Monterey sandstone Oriskany. 



This folio was published in 1894. The Franklin folio, published two 

 years later (1896), included the statement that " the implied correla- 

 tions with other stratigraphic areas are not necessarily accepted," and 

 under Monterey, in the text, " the fossil remains in this formation are in 

 greater part those which are typical of the Oriskany formation of New 

 York. Under Romney shale, in the same text, appears the statement 

 " the Romney shale contains fossils, including species distinctive of the 

 Hamilton group; those in the lowest beds comprise some species. char- 

 acteristic of the Marcellus," and under Jennings formation " fossils occur 

 in various beds in the Jennings formation and represent the Chemung 

 fauna." 



In volume I of the Maryland survey (page 182) " four divisions are 

 recognized in the sequence of Devonian deposits, known as the Monte- 

 rey, Romney, Jennings, and Hampshire formations." 



The inexact nature of this equivalence is indicated in the more de- 

 tailed " Report for Allegany County, Maryland," in which the old name 

 Oriskany is adopted for the first divisions, and the Romney formation 

 is described as " corresponding in the main with the Marcellus and 

 Hamilton formations farther north " (page 103). The Jennings forma- 

 tion is described as " closely related to the Chemung and Portage of the 

 Pennsylvania and the New York Geological Surveys " (page 106), and 

 the Hampshire formation is said to be " approximately equivalent to 

 the Catskill of the north " (see page 108). 



In the case of the Romney formations a twofold paleontological divi- 

 sion of the formations is already claimed by Prosser * It is evident 

 that the classification and nomenclature adopted in the earlier studies 

 of these formations is based on a general homotaxial equivalence and 

 not upon either exact lithologic or paleontologic likeness of the forma- 

 tions or their contents. A more minute examination of the fossil con- 

 tents demonstrates a lack of parallelism, as is shown by Prosser's paper 

 on the Maryland section and by my Bulletin 244 for the sections farther 

 south in Virginia, West Virginia, Kentucky, and Indiana. 



We are therefore obliged to question the propriety of calling the forma- 

 tions of the central Appalachian area, namely, Romney, Jennings, and 

 Hampshire, as " exact synonyms " of Hamilton, Chemung, and Catskill. f 

 In the case in question the facts seem to be established that a general 



* Journal of Geology, vol. xii, 1904, pp. 361-372. 



fSee Bulletin 191, U. S. Geol. Survey, pp. 351, 211, and 18G. 



