Devonian Shales of Ohio and Pennsylvania. 43 



Senecaii, Chan tan quaD, etc. includes the Cattaraugus, Oswayo 

 and Knapp beds of New York section." 



" The Bradfordian faunas are equally distinct from those of 

 the Chemung group, on the one hand, and those of the 

 W^averly, on the other. They contain to some extent an inter- 

 mingling of Carboniferous and Devonian species, and are in 

 fact transitional between those of the two eras corresponding 

 to the position of the rocks in which they are found." 



In Professional Paper No. 71"^ Girty states that this series 

 includes the Bedford, Cleveland, and Chagrin (Erie) forma- 

 tions in Ohio. In another placef he correlates it with the 

 Pocono and part of the Catskill and also in western Pennsyl- 

 vania with the "Piceville and considerable thicknesses of 

 underlying beds." 



It appears from the above conflicting correlations that the 

 stratigraphy of northwestern Pennsylvania was but vaguely 

 understood at the time the term Bradfordian was proposed. 

 For if we should accept them as they stand it would mean 

 including all the upper Devonian (from the Onondaga Lime- 

 stone to the top of the Chemung) and the lower Mississippian 

 (Pocono) in this new interval which is surely not warranted by 

 the facts. If we limit the term strictly to its original meaning, 

 i. e. beds including the Knapp, Oswayo and Cattaraugus of 

 New York, then its correlation is not difficult. Butts considers 

 his Conewango as the equivalent of the Cattaraugus and 

 Oswayo formations of New York.J If then the Yenango oil 

 group is correctly identified with the Conewango and Knapp, 

 and these with the Cattaraugus, Oswayo and Knapp, the Brad- 

 fordian turns out to be upper Chemung or the western marine 

 equivalent of the Catskill of the east. One suggestion might 

 be made here. The Riceville, which occupies the interval 

 between the Knapp and Berea (Pocono), is also Catskill in age. 

 If, then, the Bradfordian be expanded to take in the Kiceville 

 also it becomes a very useful term and represents, as explained 

 above, the typical marine facies of the continental and palustrine 

 Catskill found further east. 



It is assumed that the term Catskill will not be misunder- 

 stood. Stevenson and Darton have shown years ago that the 

 Catskill is the eastern facies of the Portage and Chemung. 

 Also it is well known that the characteristic lithology of the 

 Catskill extends farther and farther to the w^est as w^e rise in 

 the geological scale. So that finally and at a time correspond- 

 ing to the upper Chemung of western New York typical 



* Index Stratigraphy North America p. 421. 



f The Relations of some Carboniferous Faunas, Pro. Wash. Acad. Sci., vol. 

 vii, p. 7, 1915. 

 tOp. cit. p. 32. 



