420 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvi. 



ever, more than 20 miles apart, this New Scotland shale horizon is 

 always about '20 feet thick, upon which follows conformably, but 

 with a sharp litholog-ic ditferenee, the black siliceous shale of the 

 Lower Oriskany. 



A noteworthy fact connected with these shales at Twenty-first Bridge 

 is the occurrence of mang-anese-phosphatic nodules, which have the 

 general aspect of those dredged from the present deep seas. These, 

 however, in this case do not indicate deep waters, since the strati- 

 graphic evidence denotes a shallow sea before and after New Scotland 

 time in the Cumberland area. 



Onshany formation. — In western Maryland, upon the shale beds 

 of the New Scotland, and sharply separated from it, lies the black 

 siliceous shale with a meager fauna. That collected recalls the Oris- 

 kany of Camden, Tennessee, and point to an older stage than the 

 Oriskany as usually known. This horizon gradually passes upward 

 into the arenaceous limestone containing the well-known Oriskany 

 fauna. It does not, however, occur in full force until nearly 200 

 feet above the base of the formation, and the fauna then continues 

 through the upper 150 feet. It is these uppermost Oriskany beds, 

 just across from Cumberland, along the banks of the Potomac in 

 West Virginia, which now furnish the local collectors with fine 

 fossils. Mr. Andrews, however, secured the specimens described by 

 Hall mainly from two quarries, now abandoned, in the city of Cumber- 

 land. One of these is on Green street, below the Episcopal Church, 

 and the other is back of the German Lutheran Church. Both are 

 in the upper 75 feet of the Oriskany, as in the Green street quarry 

 the Marcellus shales plainly mark the top for measurement. How- 

 ever, at these quarries, and particularly in the one back of the 

 German Lutheran Church, on Schriver's hill, the excavation was 

 carried far below the surface into lower layers that are not shown 

 in West Virginia. This explains why certain forms, as S2>irif<'r 

 enmherlandise^ S. trihulls.^ etc., no longer, or but rarely, are found 

 about Cumberland. 



A peculiar condition of leaching of the Oriskany in this locality has 

 made it possible to secure its fossils, completeh" weathered out of the 

 inclosing rock, as siliceous pseudomorphs. This condition is restricted 

 to Cumberland, and the reason for it will be shown presently. So 

 many of these delicate fossils have been sent out by local collectors 

 that it has become a general l^elief that they can be secured anywhere 

 in the Oriskany of Maryland. Regarding this preservation Hall " has 

 written: 



While in the State of New York the accessible portions of the rock furnish us for 

 the most part with casts of its fossils, or, if beyond the reach of weathering, with a 

 compact mass of calcareous sandstone in which the fossil remains are closely 



«Paleontology of New York, III, pp. 401-402. 



