800 FLORAL ZONES OF THE POTTSVILLE FORMATION. 



States. Pseudopecopterls ohtusiloha var. iRarloj)teroides^ Sphmopteris 

 suhpinnatijida^ Oligocarjna (yremdata^ and Neuropteris tenuifoUa var. 

 kumilis seem to foreshadow as many Coal Measures types, while 

 Sp/umopteri.s /areata^ frequently reported in the lower portion of the 

 Lower Coal Measures, is, however, generally more common in the top- 

 most beds of the Pottsville formation. As elsewhere remarked, I 

 have not seen the typical form of Aht/(02:>teris lonchitica in the Lower 

 Coal Measures of the Northern States ; the same may be said of Trigo- 

 nocurpum Xocggerathi As to whether bed L represents approxi- 

 mately the horizon of Lykens coal No. 1 in the type section, little 

 that is detinite can be said. The fact is simply that the flora of each 

 bears nearly the same relation to the older floras, and to those of the 

 Lower Coal Measures, yet there are but few species common to the 

 two. It is not unlikely, however, that the latter circumstance is 

 largely due to the meagerness of the material from the roof of Lykens 

 coal No. 1. 



The general biologic evidence, treating the subject from the stand- 

 point of the composition, vertical range, individual relations, etc., of 

 the species, would seem to indicate a similar stage for both. Reason- 

 ing from the same evidence, we may conclude that the two beds are 

 referable to horizons not far distant at most. It would also appear 

 slightly more probable that the older terrane may be bed L in the 

 type section. However, very little weight should be attached to so 

 tentative a supposition, even though the latter is supported by the cir- 

 cumstance that the interval between bed L and the Twin coal in the 

 type section is over 375 feet, while Lykens coal No. 1, about 300 feet 

 from the "Buck Mountain" coal, the supposed equivalent of the Twin 

 at I^incoln, approaches within 225 feet of the same horizon at Good 

 Spring. The known variability of the Pottsville terranes is too great 

 to entitle a relative distance of that extent to any serious consideration 

 when the localities are so far removed. • 



FLORA OF THE UPPER INTERMEDIATE DIVISION. 



PLANTS OF IJEDS M AND X IN THE TYPE SECTION. 



On passing to the consideration of the species in beds ^I and N of 

 the type section, it is important to bear in mind that the floras of the 

 roof of the upper Lykens coal No. 1, at the Lincoln mine, and of bed 

 L, 380 feet below the Twin coal at Pottsville, are essentially very 

 distinct specifically from the flora of the roof of the "Buck Moun- 

 tain" (Twin) bed, as will be shown later. The phuits of Lykens coal 

 No. 1 and of bed L, which we have tentatively assumed were nearly 

 contemporaneous, are, in fact, characteristic of a zone in the upper 

 part of the Pottsville formation, and are closely ])ound to the flora of 

 the preceding Lykens coals Nos. 2 and 3, or of beds H, I, and J, 



