WHITE.] FLOKAS OF THE LOWER LYKENS DIVISION. 793 



Keui'o2)teris Smithsli, Sj)henoj)hi/Uum tenue, Lepidodendron alabametue^ 

 and Triq&mcarjpum Ilelence are among the characteristic species of this 

 stage of the Pottsville formation throughout the Appalachian region. 

 The most common, and therefore the .most useful of these in the 

 Southern Anthracite field are 21ar!opteris, Xeuroj^teris, and Spheno- 

 2)hyUuiH. In fact, if we were to employ a paleontologic term for this 

 portion of the section, the latter migiht appropriately be designated 

 the Marlopterk poUsviUea zone. 



COMPARISOX OF THE LOWER PORTIOM OF THE TYPE SECTION WITH 

 REFERENCE TO THE LYKENS COAL HORIZONS. 



Owing to the densely conglomeratic constitution of the basal portion 

 of the f oi-mation at the type locality, comparatively few fossils have been 

 obtained from beds A and B, which clearly belong to the Lower Lykens 

 division: but while the materials from bed B of the section are quite 

 insufficient to form a basis for horizontal comparisons, we find that 

 the presence of 2fariop)terls sp. No. 1, which is perhaps insepara])le 

 from Mariopteris eremopteroides, Neuropterh Pocahontas, and Spltenop- 

 teris pafentlssima in bed C, 770 feet below the Twin coal, is entirely 

 compatible with a stratigraphic position not far from Lykens coal No. 

 5. At the same time, the presence in bed D, 710 feet below the Twin 

 coal, of Mariop)teris jyottsvillea, Sphenopterh dadeana, Aloiopterisgeor- 

 glana, Neuropteris Pocahontas var. inmqualis, Muropterls Smithsii, 

 and SphenojyhijIJuni tenue strongly points to a place -near the level of 

 Lykens coal No. 4. Although several species are known to occur in 

 beds above No. 4, they are rare in higher horizons, while the more 

 important percentage of species which appear to be largely character- 

 istic of the Lower Lykens division more than counterbalances them. 

 Of greater correlative value, however, are such species as Mariopteris 

 pottsvillea, Neuropteris Smithsii, and Sphenophyllmn teriue, which are 

 in general characteristic of the horizon of No. 4 coal, and whose evi- 

 dence is strengthened by the accompanying species enumerated above. 

 In short, the plants of "bed D indicate a horizon approximate to that 

 of the Lykens coal No. 4 (White\s bed), about 710 feet below the Twin 

 coal in the type section. It is probably not higher; it may be slightly 

 lower. Bed C, on the other hand, 770 feet below the Twin coal, is 

 probably lower than the No. 4 coal, and may have been deposited at 

 the same time as the Lykens coal No. 5. 



I do not wish to be understood as regarding the coals adjacent to 

 beds C and D in the type section as unquestionably identical with 

 Lykens coals 5 and 4, respectively. The obvious variation in the beds 

 of the Pottsville formation, especially as regards the number of the 

 coals, as shown in sections located but a few miles distant, and the 

 frequentlv observed entire disappearance of the principal coals of 



