850 FLORAL ZONES OF THE POTTSVILLE FORMATION. 



the Lower Lvkens group, is nearly or quite of workable thickness, 

 have lieen found in every district where a thorough search has lieen 

 made. They are also found to extend along the base of the rising- 

 axis in Short Mountain. Furthermore, it has been shown that, owing 

 to the presence of an uno])served fault which cuts off the whole or 

 nearly all of the Potts\-ille formation at I^orberry and Fishing Creek 

 gaps, not only were the soft, inferior Productive Coal Measures coals 

 exploited at tliese gaps mistaken for degenerate developments of the 

 Lvkens coals, and consequently pronounced inferior or worthless, but 

 on account of the trend of the former coals along the north side of 

 Sliarp Mountain the. entire Fottsville group of coals has been sup- 

 posed to lie to the north of the crest of the mountain. The outcrop, 

 or su})posed approximate outcrop, of the lowest Lykens coal was there- 

 fori' mapped by the late anthracite survey of Pennsylvania' along or 

 near a horizon not lower in most places than the horizon of the Buck 

 jNIountain coal, the conventional base of the Lower Coal Measures, 

 from Fishing Creek Gap to a point about 2 mil(\s west of the Rattling 

 Run (nip, an entire distance of over IT miles. To the same misinter- 

 pretation at Lorberry and Fishing Creek gaps is also due the fact that 

 no systematic search has ever ])een made for coals south of the crest 

 of Sharp ^Mountain (where no coals were supposed to occur) between 

 Fi-liing Creek Gap and Rattling Run Gap. 



It must not ])e understood from the above statement of facts that 

 Lykens coals in good condition lie awaiting the search of the pros- 

 pector along the south slope of Sharp ^Mountain. On the other hand, 

 the vertical or very highly inclined attitude and the often crushed or 

 slipped condition of the other coals along Sharp Mountain render it 

 proljal)le that the Lykens coals will here also be found generally infe- 

 rior in structure, and perhaps in composition, as compared with the 

 present standard requisite for protitable mining. It is the purpose of 

 this review of the stratigraphy of the region not merely to secure 

 greater accuracy in the mine maps of the Dauphin Basin, or to add 

 to our knowledge of the floras of the Pottsville formation in this 

 region. l)ut to call attention to the facts: (1) That the soft or semi- 

 bituminous coals on the north slope of Sharp Mountain between Fish- 

 ing Creek and Rattling Run gaps, hitherto regarded as the Lykens 

 coals, are really in the l*roductive Coal ]\[easuri>s; (2) that practically 

 no search" has been made for coals in the Pottsville formation through- 



'Crwlit is due the opinion expressed by Mr. A. DW. Smith in a footnote to the Summary Final 

 Report of the State Survey (p. 2140), that the outcrops of the red shale and the lowest Lykens coal 

 are drawn 800 to 1,000 feet too far north between Lorberry Gap and Rattling Run Gap, most of the 

 coals in the Lorberry and Fishing Creek gaps being referable to the Lower Coal Measures, although 

 he assumes the full thickness of the Pottsville formation to be present at the latter gaps. This foot- 

 note, which I had Tiot seen until the writing of the i>resent i>apcr, is (juite at variance with all other 

 portions of the text relating to tlie Dauphin Basin in Mr. Smith's report. 



-'Kxceptions of little importance are the discoveries of the Reliance coal at Rattling Run <iapand 

 the thin coal near the top of the Pottsville formation in Rausch Gap, section 2, PI. CLXXXVll. 



