INTRAFORMATIONAL PEBBLES IN RICHMOND GROUP 305 



One of the causes giving rise to widespread current-action may 

 have been violent and widespread storms. Considering the fact 

 that the Cincinnatian strata were deposited in epicontinental 

 seas, storms easily, at times, might have blown vast quantities of 

 water over those parts usually covered only by shallow waters. 

 Such storms occasionally are experienced on the Gulf coast, and 

 along the coast of the southern Atlantic states. The ebb flow 

 of these accumulated waters, after the storm, might easily give rise 

 to widespread ripple-marking of the last deposited strata, even at 

 a considerable distance from actual shore lines. Such an origin 

 of currents would predicate wide areas of gradually shallowing 

 seas over which the surface waters blown before the wind would 

 tend to accumulate. Currents due to such causes might be 

 expected more readily in the comparatively shallow waters of 

 epicontinental seas than along the more abrupt shores of the deeper 

 oceanic basins. 



The presence of numerous well-preserved colonies of Protarea 

 and of delicate growths of Stomatopora and other bryozoans on 

 the upper surface of the pebbles at the Elk Run locality, east of 

 Winchester, Ohio, is indicative of submerged conditions at least 

 immediately after the formation of the pebbles. In a similar man- 

 ner, the long crinoid columns found on the surface of the ripple- 

 marked layers of lower Trenton limestone, at Hull, in Canada, 1 

 indicate that fairly deep waters were present immediately after the 

 formation of the ripple-marks, and may have been present even 

 during their formation. 



Ripple-marks comparable in dimension with those character- 

 istic of the Ordovician limestones of Ohio, Indiana, and Kentucky 

 are not unknown along our present shores. They occur where 

 waters accumulating in extensive salt marshes or in estuaries during 

 high tide find a ready outflow to the sea during ebb conditions. 

 In these cases the steeper slopes of the ripple-marks are directed 

 away from the shallower waters. 



It is remarkable, however, in the case of the ripple-marks on 

 the Ordovician limestones of the areas here under discussion, how 



1 Kindle, Jour. Geol., XXII (1914), 712. 



