WHiTE.J THE FAULT IN SHAKP MOUNTAIN. 839 



heavy nor numerous. The reason for this fact will appear upon an 

 examination of the fossils obtained at the south drifts. The flora col- 

 lected from the lower drift, the supposed Lj^kens No. ♦>, on the east 

 side, includes: 



Sphenoi:»terif! cf. mixta Schiinp. 

 Oligocarpia cf. Brongniarti Stur? 

 Pecopteris pusilla Lx. 

 Pecopteris unita Brongn. 



Pecopteris Miltoni Artis. 

 Pecopteris polymorpha Brongn. 

 Neuropteris ovata Hoffni. 

 Annularia stellata (Schloth.) Wood. 



That from the drift, about 50 feet higher on the same side, reveals: 



Mariopteris cf. cordato-ovata (AVeiss) . I Neuropteris ovata Hoffni. 



Pecopteris oreopteridia (Schloth.) : Neuropteris plicata [Lx.]. 



Sternb. j Neuropteris C'larksoni Lx. 



Pecopteris arl)orescens (Schloth.) Brongn. | Neuropteris Schenclizeri Hoffm. 



Alethopteris pennsylvanica Lx. ? Calaniites Suckowii Brongn. 



Sjjhenopterls plnnatifida (Lx.), -S'. cf. GravenJujr.stll Brongn., and 

 Cordaites serpens Lx. are additional species gathered from the rock 

 dump, which mav contain shale from l)oth drifts. 



The similarity of this flora to the floras listed from the Twin coal 

 (Buck Mountain bed), in the central portion of the Southern Anthracite 

 field, or to the flora of the lower coal in Lorberry Gap, is at once 

 apparent. It, like those considered, is a pure Coal Measures flora. 



WESTERN LIMIT OF THE FAULT. 



It will be observed that the red shale is shown in PI. CLXXXVI, 

 Fig. 1, as but 247 feet below the lower coal on the east side of the 

 gap. It is not wholly improbable that the Mauch Chunk formation 

 approaches along the line to the east of the section, even to within 120 

 feet of the coal. Unless the red shales in the old clearing, about 3.50 

 feet to the east of the gap, have been transported by human agency, 

 as seems rather improbable under the local conditions, the Mauch 

 Chimk lies at that point within 100 feet of the lower coal drifted in 

 the gap. 



.•Vs lending color of probability to the assumption of the existence 

 of such a diagonal contact of the two formations, I will add that along 

 the wagon road on the west side, below the gap, I have not seen the 

 red. shale above a point about TOO feet below the lower coal mined in 

 the gap; this point is about 155 feet south of the forks in the wagon 

 road. I do not, however, question the correctness in this respect of 

 the mine map on which the shale is platted as nearh^ 110 feet north 

 of the same road forks. To the west, and for a short distance to the 

 north of this exposure, a zone of dark-brown ferruginous soil, accom- 

 panied by springs, extends in a direction apparently SSW. To the 

 east of this zone no heavy conolomcrates are s<M:>n in place, though the 

 brown tract is strewn with loose blocks from the hillside on the west. 

 This zone 1 believe to ])e alone" or near the fault line. 



