Roivley — Edgewood Limestone of Pike County, Mo. 317 



Art. XX. — The Edgewood Limestone of Pike County, 

 Missouri / by R. R. Rowley. 



The Edgewood formation of T. E. Savage* begins with the 

 basal Noix oolite, followed by the Cyrene and Bowling Green 

 limestones, but the Cyrene is not at the base of the succession, 

 as stated by Mr. Savage. f 



Both C. R. Keyes;}: and Savage err in attempting to cor- 

 relate in whole or in part the Noix oolite and the Cyrene 

 member. They are very distinct not only lithologically, but 

 faunally and stratigraphically. It is probable that Mr. Keyes 

 has always considered the oolite and Cyrene members as equiv- 

 alent to each other, and naturally so, since each in certain 

 localities in Pike County directly overlies the Ordovician or 

 the Buffalo shale. The author of this article so considered 

 them for years, but he has lately been fortunate enough to 

 find a locality (the Mcllroy farm) where the three members of 

 the Edgewood are present, with the lower two horizons abund- 

 antly fossiliferons and each with its characteristic fauna. The 

 south branch of Noix creek at the big C. & A. R. R. bridge 

 near Bowling Green, repeatedly swollen by the heavy rains of 

 the spring and summer of 1915, has cut against the hillside 

 at Mr. Keyes's type locality of the Bowling Green limestone 

 and laid bare the Silurian beds, which here rest upon the 

 Buffalo shales-, presenting for study a splendid succession of 

 the Edgewood formation. The oolite, however, is wanting, 

 but the Cyrene member is present, fully developed and equipped 

 with its fossil markers, though with no line of separation to 

 distinguish it from the Bowling Green limestone above. There 

 is neither a lithological line of separation nor an apparent break 

 in sedimentation nor a change in fossil content, for the writer 

 has collected Atrypa prwmarginalis, A.putilla and Eavosites 

 subelongus from the contact with the Ordovician shale below 

 to the black Devonian ? shale above (Grassy Creek). 



More or less brown limestone, either of the Cyrene or Bowl- 

 ing Green members, always overlies the basal oolite, but there 

 is usually a dearth of fossils in it ; however, the faunae of the 

 Cyrene beds and the oolite member are closely related, despite 

 the fact that few species pass from the one into the other. 



If it were possible, as Keyes suggests, that the oolitic char- 

 acter of the basal beds in the eastern part of the county is 

 merely a local phase, then when the Cyrene limestone replaces 



*T. E. Savage, this Journal, xxviii. 1909, p. .517, December. 

 ■fT. E. Savage, Stratig. and Palaeont. Alexandrian Series in 111. and Mo., 

 pp. 19, 25. 



JC. E. Keyes, Proc. Iowa Acad. Sci., vol. iv, p. 27. 



