it '2 FLOKAL Z()NP:S OF THE POTTSVILLK FOKMATIOX. 



localities appait'iitly ict'erahh* to tlic I'ppcr Lykciis oronp. To make 

 clear the paleoiitolouic sioiiiticance of this division, the species are 

 systematically grouped in two sections, the first including those 

 observed in the Lower I^ykens division, the other containing the 

 reniaindei' of the species. 



(Tenerally speaking, the collection of phints in the I'ottsvilli' forma- 

 tion is more dithcult than in the succeeding Coal Measures, not only on 

 account of the frequent occurrence of conglomeratic stindstone in the 

 roof of the coals, but also on account of the usually fi'agmentary con- 

 dition of the vegetable material, which prevailingly seems to have suf- 

 fered severely, as might l)e expected from the composition of the 

 environing terranes. through the exigencies of driftage. As is natu- 

 ral, the larger collections, containing the greater proportion of the 

 species, were obtained from the rock dumps at the collieries, or from 

 the more projiitious plant l)eds in the gap sections, while the material 

 from beds in which fossils are very scarce or poorly prc^served is. in 

 spite of considerable persistence in collection, often conspicuously scant. 

 It thus happtMis that some of the examples from a bed are too frag- 

 mentary for certain specific identitication with remains foimd elsewhere; 

 and tlu^ presence of the species at these localities is. accordingly, 

 doubtful and indicated by a (|uerv. Another difficulty atiecting the 

 stratigraphic refereiu-e of the specie's arises from the collection of large 

 (piantities of material, including the 1)est fossils, from mine dumps 

 receiving the roof shales from two or more coals, so that it Avas at 

 tirst found impossil)le to ascertain from which of the coals a given fossil 

 was derived. However, by a painstaking study of the plants and their 

 associations on slabs obtained from derinitely tixinl beds at other points. 

 or procured thi-ough the unfailing courtesy of the local engineers, 

 superintendents, and mine forenuMi. directly from the interior of the 

 mines, it later became possible to assign nmch of th(> matm'ial from 

 the' rock dumps, either detinitely or api)roximately. to their oi'iginal 

 sources. Such references, made with great caution, are indicated in 

 the respective t-olunms by numbers referring to the coal from whose 

 roof the specific fossil came. 



A discussion of the significance of the composition of the tlora and 

 the range of the species will receive attention in coniuH-tion with the 

 subject of the age and e(|ui\alents of the formation. Hcononiy of 

 space forbids the description of the species in this report. Many 

 of them are new. while many otliers have been the subject of careful 

 revision. A few only will here recei\(' any systematic biologic treat- 

 ment. The descriptions of all the material in hand are now complete, 

 and will form part of a monograph, in process of preparation, on 

 the flora of the Pottsville formation in the Appalachian i)rovince. 

 Their ])resent publication \voul<l therefore lead to duplication. 



