60 The Middle Devonian Deposits of Maryland 



end in the railway cuts clircotl}' north of the 21st Bridge station on the 

 Baltimore and Ohio E. E. This locality is IVl miles northeast of 

 Monster Eock and the Oriskany sandstone and Helderberg limestones are 

 well shown in the Baltimore and Ohio R. R. cut on the West Virginia 

 side of the river. On the Maryland side of the river just above the railway 

 bridge is a contact of the Oriskany sandstone and Eomney formation. 

 In the ridge to the east of the West Virginia Central R. R. cut the 

 folded Oriskany sandstone is nicely shown. The sections of the Onondaga 

 member in this vicinity are described by Kindle on a preceding page. 

 In the West Virginia Central R. R. cut to the west of the river the black 

 shale and blackish limestones at the top of the Onondaga member are 

 exposed. 



The rocks dip steeply down to the cut of the Baltimore and Ohio R. R. 

 which is directly below and only a short distance north of the 21st Bridge. 

 At the southern end of the latter cut are thin, argillaceous, black shales, 

 weathering to a rusty brown or iron color, which are somewhat above 

 the limestones in the West Virginia Central R. R. cut. In some of the 

 layers which are a little more arenaceous and tougher than most of the 

 shales Liorhynclius Umitare (Vanuxem) occurs abundantly, associated 

 with an occasional other fossil. Some of the specimens of Liorhynchus 

 are very perfect representatives of the species. Many of them, however, 

 in the thin black shales are greatly crushed so that they are as flat as those 

 occurring in the fissile black shales of New York, which they closely 

 resemble, while some of the specimens from the coarser shales are gib- 

 bous retaining the normal form of the species. From these shales the 

 following species were obtained : Camarotoccliia prolifica Hall ( ?) 

 (poorly preserved specimens), Liorlujnclius Umitare (Vanuxem), Tropi- 

 doleptus carinatus (Conrad), BracMopod sp. (specimens that seem to 

 have a pustulose or punctate structure, something like Spirifer fimbriatus 

 but there is no fold or sinus and rather coarse plications cover the entire 

 surface), NncuIUes triqueter Conrad ( ?) (very imperfectly preserved). 



The shales here and there contain small somewhat calcareous concre- 

 tions in which are numerous specimens of Liorhynclius Umitare (Van- 

 uxem) while some of the concretions are larger and moi'c calcareous. 



From the range of the species it will be seen that the fauna is similar 



