140 H. S. WILLIAMS — NOMENCLATURE AND CLASSIFICATION 



doubtless true that no practical evil is likely to result from assuming the corre- 

 sponding beds to be synchronous or strict^ contemporaneous, and there are mul- 

 titudes of accessory circumstances which may fully justify the assumption of such 

 synchrony. But the moment the geologist has to deal with large areas or with 

 completely separated deposits, then the mischief of confounding that ' homotaxis,' 

 or 'similarity of arrangement,' which can be demonstrated, with 'synchrony,' or 

 ' identity of date,' for which there is not a shadow of proof, under the one common 

 term of ' contemporaneity ' becomes incalculable and proves the constant source of 

 gratuitous speculations." * 



Discussing this same problem, Geikief says: 



" Strict contemporaneity can not be asserted of any strata merely on the ground 

 of similarity or identity of fossils." 



Illustrations of Importance of stratigraphic rather than Time 



Basis 



in general 



Iii the bulletin (number 244) referred to two or three particular cases 

 are elaborated which exhibit the importance of using a purely strati- 

 graphic basis in discussing the relations of faunas to formations and 

 of freeing the definition of formations from all time designations. The 

 geologist is referred to the bulletin for details. Only the main facts will 

 be here mentioned. The three cases to which attention is called are as 

 follows : 



MONTEREY, ROMNEY, AND JENNINGS BEDS OF VIRGINIA AND WEST VIRGINIA 



First, the faunal combinations and successions in numerous sections 

 cutting through the beds called Monterey, Romney, and Jennings, in 

 Virginia and West Virginia, were analyzed. The facts developed show 

 that at the base of the beds called Romney occasionally a few fossils of 

 the Corniferous and Hamilton of New York, but thereafter the Marcel- 

 lus, Genesee, and Portage (New York), faunas dominate, to be followed 

 above by Chemung types in cases where these latter are not altogether 

 wanting. In the cases where the Hamilton species appear they are 

 associated with Corniferous forms and lie below the typical black shales 

 called Romney (in Virginia), a formation reported to be the equivalent 

 of the Hamilton and Marcellus. 



CATAWISSA SECTION OF PENNSYLVANIA 



The second case is that of the Catawissa section, in central Pennsyl- 

 vania. After passing above beds which faunally and lithologically are 



* Loc. cit., p. xlvi. 



f A. Geilcie: Text Book of Geology, second edition, 1885, p. 608. 



