414 CHARLES S. PROSSER 



"there are beds at Cumberland, Md., holding a fauna of the age 

 between the Lockport [Rochester?] shale and the Guelph of 

 New York and Ontario. This fauna has its peculiarities, but the 

 aspect is certainly not Clinton."' 



Salina formation. — This formation borders the Niagara but the 

 rocks are largely concealed over most of the areas except along 

 Wills Creek in Cumberland, Flintstone Creek at Flintstone, and 

 the Baltimore and Ohio Railroad near Potomac Station, where 

 one finds the best exposure. In the Potomac section there are 

 four cement beds which have great economic value, the lowest 

 one situated about twenty-five feet above the base of the forma- 

 tion. Fifty feet of the succeeding 140 feet of the formation is 

 composed of the four cement beds which are separated by shales 

 and impure limestones. Succeeding the upper cement bed are 

 450 feet or more of gray shales, drab and blue limestones 

 and sandstone, the limestones predominating.^ The thickness is 

 about 700 feet. Fossils are not common. The formation was 

 named from Salina in central New York and is represented by 

 No, V^ of the Pennsylvania survey and the second part of the 

 Lewistown formation of the Piedmont folio. 



The statement has been made that " the geological reader 

 will wonder on what basis the name Salina is applied to the rocks 

 so described" in Maryland. ^ It is perhaps sufficient to state 

 that Professor Lesley, the former state geologist of Penns^-l- 

 vania and admirable stratigraphical geologist, correlated the 

 corresponding rocks of Pennsylvania with the Salina. In Bed- 

 ford county, Pennsylvania, which lies immediately north of the 

 Cumberland region, Professor Lesley gave the upper and middle 

 divisions of the Salina as 628 feet in thickness to which is to be 

 added a portion of the 472 feet composing the lower Salina 



' Letter of June 26, 1901. 



" Mr. Schuchert has recently studied this formation in the Cumberland region and 

 he writes me as follows: " I am inclined to cut out of the Salina the lower 23' 6" as 

 given on p. 93 of O'Harra's report (Maryland Geological Surve}', Allegany county). 

 This thickness I now refer to the rest of the Niagara. I also extend the Salina a 

 litile higher, making the total thickness 704'." (Letter of June 26, 1901.) 



3 Am. Jour. Sci., 4th ser., Vol. XI, p. 240, 1901. 



