850 FLORAL ZONES OF THE POTTSVILLE FORMATION. 



XXV of the Anthracite Atlas. That portion of the Dauphin Basin 

 west of Yellow Spriny's was somewhat thoroug-hly explored l)y the 

 owners, the Dauphin and Susquehanna Coal Company, under the direc- 

 tion of Dr. Taylor. It is to this fact that most of our knowledge of 

 the coals in this reg-ion is due. 



The entire thickness of the PottsvilU^ formation, from the ))ed 

 which 1 assiune to represent the Twin (Buck Mountain) coal to the top- 

 most beds of the red shale is given by Taylor as 1,100 feet. Within that 

 interval twelve coals were found. Two thin coals are reported within 

 170 feet of the red shale. The sixth coal from the red shale, the 

 Reliance l)ed, not over 3 feet in thickness, was drifted for -lOl feet. 

 Although a very "dry coal," it was not found tol)e at that time profit- 

 al)ly workal)le. The distance, 410 feet, from this bed to the red shale 

 suggests the position of Lykens coal No. 4. Twenty feet to the south 

 of the Keliance bed another coal was opened, and still another l)ed 

 was discovered 40 feet to the north. A coal at the supposed horizon 

 of the Buck Mountain lied has l)een opened on both sides of the gap, 

 it having l)een drifted for a considerable distance on the east side. No 

 fossil plants were obtained at this gap. 



BIG FLATS. 



(Statiox 20, PL. CLXXX.) 



As Sharp and Stony mountains, which form the two walls of the 

 Dauphin Basin, converge toward the west, the interior valley becomes 

 less marked, until at a point nearly opposite Watertank Station, 

 about 9 miles fi'om Dauphin, the Coal Measures completely till the 

 interval from rim to rim and form a low, slightly convex knob, 

 the Big Flats, about 1 mile in length, the north and south faces being 

 composed of the Pottsville formation. The topography is shown on 

 the Harrisburg sheet of the Topographic Atlas of the United States, 

 as well as on mine sheets xxv and xxvi, Ft. Ill of the Anthracite 

 Atlas. The shaftings on the Big Flats, dating from the early part of 

 the century, are described by Tavlor, whose cross section was repro- 

 duced by Rogei's.' Dr. Taylor reports the presence of three coals 

 within an interval of 48 feet, from one of Avhich several hundred tons 

 of coal were hauled to the Susquehanna River at Dauphin prior to 

 1840. The three principal shafts, l)ut a few yards apart, are platted 

 on mine sheet xxvi. The shale from the shafts is now nearly disin- 

 tegrated; yet fragments taken from the duni]) reveal the presence of 

 Xruroptri'tx oriiid Ilollin.. N. ScJuKehzei'l IIollui.. Ptcopft-vh rUJom 

 Brongn. ^ Arnt nhi rhi t<tellata {^Ki\Aoi\\.)\s oo(\., and S2)h</n(>ph >/U um emar- 

 i/iiHifiiiii Brongn., species chai'acteristic of the Lower Coal Measures. 



Althouiih we have no measurements showing the thickness of the 



' Geol. Penusylvanitt, Vol. II, Pt. I, p. 198, fig. 184. 



