MARKINGS IN PENNSYLVANIAN SANDSTONES 67 
The writer is indebted for information and suggestions regard- 
ing these markings to his former associates on the United States 
Geological Survey, Clarence 5. Ross and Kenneth C. Heald. 
The best localities were found by R. H. Wood and D. D. Conduit 
of the Survey. 
CONDITIONS OF SEDIMENTATION 
During the middle and upper Pennsylvanian, when shales, 
sandstones, and limestones of the Osage were being deposited, 
a shallow sea with a continually oscillating shore line covered 
eastern Oklahoma and Kansas, and west-central Texas. The 
axis of the basin extended in a northeast-southwest direction with 
the southeastern shore line not far east of the eastern Osage and 
near the present outcrop of the Strawn formation in Texas.’ The 
territory in Oklahoma in which the markings are found lies in 
the eastern Osage between Pawhuska, Hominy, Skiatook, and 
Tulsa. In this region limestones are thin and few, but highly 
fossiliferous. ‘The sandstones commonly show ripple, current, and 
other strand markings; occasionally they are fossiliferous.? Strati- 
graphically the grooves are known in various horizons between the 
Hogshooter limestone and the Elgin sandstone, 1,000 feet apart. 
The Strawn formation in Texas is older than any of the Osage 
sediments. 
DESCRIPTION OF MARKINGS 
Nothing unusual has been noted in the current, ripple, and 
rill marks in the Osage sediments except that the current and 
rill markings appear in various stages of obscurity and some of 
the markings defy classification. They appear both on the upper 
and lower surfaces of sandstone layers. The nature of the parallel 
groovings may be judged by the photographs. 
Localities in the Osage where markings may be seen are numerous. A 
few are given in the following list: (1) S.E. cor., N.E. 7, Sec. 8, T. 20 N., 
_R. 12 E,, near F. A. Gillespie No. 1 (by R. H. Wood and the writer); (2) on 
t Mr. A. W. McCoy, of Bartlesville, Oklahoma, has prepared extensive manuscript 
paleogeographic maps of these seas and has kindly given the writer the foregoing in- 
formation and the correlation of the beds. 
2 “Structure and Oil and Gas Resources of the Osage Reservation, Oklahoma,” 
U.S. Geol. Survey, Bull. 686 (1919). 
