RIPPLE-MARKS IN OHIO LIMESTONES 459 



is given by Dr. Foerste as 60 feet below the top of the Richmond 

 formation. 1 



The dip downstream carries this ripple-marked layer down Elk 

 Run to where it covers the entire bed of the stream for some dis- 

 tance above the highway bridge. At this locality the bed of the 

 stream which is covered by the ripple-marked layer is some 60 feet 

 wide and extends 156 feet along the bed of the stream. This is a 

 beautiful example on a large scale of a ripple-marked limestone. 

 The trend of the crests of some of these ripple-marks is N. 3 W., 

 and they undulate to a considerable extent in crossing the stream. 

 The crests of the normal ripple-marks are from 27 to 32 inches 

 apart. The crests of about three out of five are 29 inches apart, and 

 the average over different parts of the surface of this layer is 29, 

 30, and 31 inches apart. The more gradual and longer slope 

 (stoss) is to the east, the steeper and shorter slope to the west, and 

 the ripple-marks are clearly asymmetrical. A view of the ripple- 

 marked bed of Elk Run at this locality, looking downstream 

 toward the highway bridge, is shown in Fig. 2. A view of the bed 

 of Elk Run from the highway bridge looking upstream, with the 

 railway trestle in the distance, is shown in Fig. 3. 



The layers on the western side of Elk Run below the highway 

 bridge are dipping from 3 to 4? 5 N. io° E. The majority of 

 readings on the different layers, however, gave 3 for the amount of 

 dip. The barometer gave a dip of 5 feet to the east for the surface 

 of the ripple-marked layer from the branch to the bed of Elk Run 

 under the highway bridge, a horizontal distance of 500 feet. 



Just below the highway bridge on the western bank is a ripple- 

 marked layer, between 2 and 3 feet higher than the fine one in the 

 bed of Elk Run which has just been described. The ripple-marks 

 of this higher layer run N. 30 W., are not so conspicuous as in 

 the lower layer, and do not show much difference in the slope of 

 the two sides. On the western side of Elk Run, not far below the 

 highway bridge, is the house of Mr. Charles L. Bailey, and near 

 water-level above the house is a set that runs about northwest 

 and southeast. The eastern slope of these ripple-marks is more 

 gradual than the western slope. Just below the Bailey house a 



1 Ibid., p. 58. 



