WHITE.] PURPOSE AND SCOPE OF PAPER. 757 



formation any reliable and distinct paleontologic characters or aspect? 

 is it satisfactorily distinguishable by means of fossils from the subja- 

 cent formations or the overlying Coal INIeasures :' and does the plant 

 life reveal such moditications in time, or such vertical distribution, as 

 to constitute paleontologic subdivisions, zones, or horizons ? In answer 

 to these inquiries, it must be confessed that up to the present time 

 nothing has been known of the plants or their associations in the type 

 section. No one appears to have studied the fossils from the Potts- 

 ville formation in the vicinity of the type section in the Pottsville 

 Basin, or even in the entire Southern Anthracite coal held. In tak- 

 ing up the task of the stratigraphic elaboration of the Pottsville flora,^ 

 it was further discovered that neither the upper nor the lower limits 

 of the '"Serai" conglomerate, or "Pottsville conglomerate," are 

 closely defined by the earlier geologists, while the somewhat conven- 

 tional lithologic boundaries proposed in the latest publications on this 

 subject appear to lack general acceptance. 



PURPOSE AND SCOPE OF THIS PAPER. 



As will have been inferred from the above statements of existing 

 conditions and needs, the purposes of the studies, the immediate results 

 of which are preliminarily reported in this j)aper, are: 



(1) The exploitation and elaboration, from a stratigraphic stand- 

 point, of the plant fossils of the Pottsville formation in the tvpe 

 region in the Southern Anthracite coal field. This involves the volumi- 

 nous collection of fossils from as many horizons as possible, ranging 

 throughout the entire thickness of the formation, as somewhat uncer- 

 tainly defined on the lithologic basis. 



(2) The critical analysis and comparative study of the plant material 

 collected, with a view to the discover}^ of the existence of anv natural 

 paleontologic subdivisions, zones, or horizons, and their paleontologic 

 characters, or the species of stratigraphic value, if any such are 

 present. 



(3) The discover}^ of the paleontologic limits as differing or as 

 agreeing with the lithologic limits of the type section, and the conse- 

 quent paleontologic definition of the formation. This entails the 

 examination of the fossils in the terranes below the Pottsville, as well 

 as in the lower portions of the Coal Measures above the lithologic 

 Pottsville, and the determination of («) their relations to the floras of 

 the latter, and (b) the significance of those relations in both the geo- 

 logic and the paleontologic grouping of the formation. Since, as has 



1 Lest the use oi the word " paleontology" in this report be considered an unwarranted assumption 

 by those who are accustomed to understanding the term as applying exclusively to animal remains, 

 it should be explained that fossil plants in general are not only most widely distributed and frequently 

 the only fossils in the terranes on the east side of the Appalachian trough, but also that in many of 

 the sections, including the type section at Pottsville, no animal fossils, with the exception of Spiror- 

 bis, small, rare, crustacean fragments, and a few cockroach wings, have yet been discovered. 



