472 STEVENSON— THE FORMATION OF COAL BEDS, t-^ov. i, 



Cumberland and Rhea counties, Tennessee, the former being on the 

 western, the latter on the eastern outcrop ; Foster described a coarse 

 sandstone on Licking River, Ohio, with ripple marks and indistinct 

 fucoids, the latter being most probably casts of sun cracks. White 

 reports the flags at a quarry in Mercer county of Pennsylvania a? 

 showing both ripple marks and rain prints. 



The writer finds no record of ripple marks or sun cracks on 

 sandstones of the Allegheny. Several correspondents assert that 

 they have seen them frequently but cannot remember the localities 

 as no entries were made in the note books. Condit*^ observed 

 excellent examples in the Conemaugh of Ohio at 15 feet below the 

 Pittsburgh coal bed and at 60 feet below the Ames limestone. 

 Stevenson saw in Fayette county of Pennsylvania a Conemaugh 

 sandstone of which the layers, exposed in a quarry, are covered with 

 irregular ripple marks, closely resembling those made by winds on 

 dunes or sand plains. A laminated sandstone at 57 feet below the 

 Pittsburgh coal, in Allegheny county, is ripple marked on many 

 of the surfaces. In Fayette county, the shales overlying the Pitts- 

 burgh coal frequently contain thin layers of ripple marked sand- 

 stone and in Greene county the Pittsburgh sandstone shows the 

 irregular trails known as Spirophyton. In Fayette and Westmore- 

 land counties, ripple-marked surfaces characterize the Waynes- 

 burg sandstone at the base of the Washington formation. The 

 uniform testimony of those who have studied the Appalachian basin 

 is that ripple marks and sun cracks are familiar phenomena in the 

 Coal Measures sandstones or in the clayey films separating the 

 layers. 



Footprints in sandstone have been reported from but one locality. 

 King long ago announced the discovery and the occurrence was 

 confirmed sometime later when he and LyelP° studied the rock 

 together. The quarry in a Conemaugh sandstone was about 5 miles 

 southeast from Greensburg, Westmoreland county. Pennsylvania. 



'°D. D. Condit, letter of February 14, 1912; J. J. Stevenson, Sec. Geol. 

 Surv. Penn., Rep. K, 1876, pp. 99> 200, 208, 309; Rep. KK, 1877, pp. 31. 208. 



^ C. Lyell, " On Footmarks Discovered in the Coal Measures of Penn- 

 sylvania," Quart. Jounu Geol. Soc, Vol. II., 1846, pp. 417-420; Vol. VII., 

 1851, p. 244. 



