658 CHARLES S. PROSSER 



DESCRIPTION OF SECTIONS 



What follows in this paper in reference to the Shenandoah 

 limestone relates more particularly to the upper part of that 

 formation which was studied to some extent in the vicinity of 

 Martinsburg, West Virginia, and Pinesburg, Maryland. 



Limestone and shale near Marti?isburg. — 1 . Along the Baltimore 

 and Ohio Railroad immediately east of Martinsburg station are 

 exposures of the upper part of the Shenandoah limestone. At 

 the western end of the cut, just east of the railroad bridge over 

 Tuscarora Creek, are dark blue, fairly massive limestones, some 

 of which, however, on weathering split into quite thin, irregular 

 layers (Fig. 1). These limestones are fossiliferous, two species 

 of Lingula, together with some other forms having been noticed, 

 and the rocks closely resemble many parts of the tvpical 

 Trenton limestone of New York. In the eastern part of this 

 cut, near the switchtender's station, there are thin layers of 

 dark blue limestone which alternate with dark blue to black 

 calcareous shales containing fragments of graptolites, and this 

 part of the cut shows a transition from the massive limestones 

 of the Upper Shenandoah to the lower shales of the Mar- 

 tinsburg formation. This part of the section is shown in 

 Fig. 2. 



3. To the east of the switch cut the rocks are covered for 

 some distance ; but about one half mile east of the station is 

 Cemetery cut, where several hundred feet of quite thin, even, 

 bluish, somewhat argillaceous shales are well shown. These 

 may be seen in Fig. 3. In a rather hasty examination no fos- 

 sils were found and the lithological character of these shales is 

 rather more like that of the Hudson in New York than the 

 Utica shale. 



4. To the east of Cemetery cut is a covered space and then 

 another railroad cut in shale follows. These shales which are 

 mainly blue and arenaceous closely resemble lithologically the 

 Hudson shales of the Mohawk Valley and Eastern New York, 

 and alternating with them are thin layers of greenish, micaceous 

 sandstone similar to those in the lower part of the Hudson in 



