176 Annals of the Carnegie Museum. 



There are numerous other unconformities of this same sort at differ- 

 ent horizons in the Conemaugh series near Pittsburgh, some of which 

 will be described and figured at another time. 



Note on the Names Buffalo and Saltsburg as Applied to the 



Sandstone Between the Brush Creek a'nd the 



Pine Creek Limestones. 



In a number of the folios of the Geologic Atlas of the United States 

 the name Saltsburg has been adopted for the sandstone designated as 

 Buffalo in this paper. The latter name has been preferred by the writer, 

 first, because it has a slight priority of publication, and secondly, be- 

 cause, although as first used the name Saltsburg was intended to desig- 

 nate the sandstone called Buffalo by Dr. White, the section from which 

 the formation was named, and which was taken as the type, shows a 

 sandstone which is really a combination of the Cow Run and Buffalo 

 sandstones. The combination was effected in the same way as has just 

 been illustrated in the section at Allegheny. Professor Stevenson 

 gives the same explanation to the Saltsburg section in the Bulletin 

 of the Geological Society of America, Vol. XVII, igo6. 



The name Buffalo was given by Dr. I. C. White in Report Q of the 

 Second Geological Survey of Pennsylvania, page 33, 1878. He states : 

 "The Buffalo (Upper Mahoning) Sandstone, 450 to 510 feet below 

 the Pittsburgh coal, is No. 19 of the section. By this name we have 

 designated a very massive and conglomerate sandstone which comes 

 immediately below the Pine Creek limestone, and attains its maximum 

 development along the waters of Buffalo Creek, in Buffalo township, 

 Butler County. In the section at Freeport it forms the upper bluff 

 rock, and its base is 125 feet above the Freeport coal." 



In Report KKK of the same survey, page 22, 1878, Dr. }. J. Steven- 

 son applied the name Saltsburg to a sandstone which "is finely exhib- 

 ited along the Conemaugh and Loyalhanna near Saltsburg." In the 

 generalized section on page 18, Dr. Stevenson represented the sand- 

 stone with the top 53 feet below the Green Crinoidal limestone 

 (Ames) and the base 42 feet above the Black fossiliferous limestone 

 (Brush Creek). It is not further defined in that report, and for a 

 fuller description it is necessary to go to the typical section, which was 

 described by the same author in Volume KK, pages 317 and 318. The 

 sandstone is there described as being 100 feet in thickness, with the 

 base resting upon ten feet of black, rather sandy shale. In this shale 



