144 E. M. KINDLE 



So far as can be judged from the literature, fossil limestone 

 ripple marks generally show a wave-length of from i to 5 feet. 

 The widely spaced ripples with a wave-length of 15 feet or more, 

 which appear to be very common on the calcareous sand of the 

 Bahama-Florida regions, do not seem to have been noted in lime- 

 stones. Ripples with a wave-length of only 2 or 3 inches appear 

 hkewise to have generally escaped the notice of geologists. This 

 apparent discrepancy between the size of the ripple marks of lime- 

 stone and that of calcareous sea bottom will probably disappear 

 when search for such features becomes more thorough. 



Ripple marks of unmistakable current-ripple type with a wave- 

 length of i\ inches and amplitude of \ inch are represented in the 

 Canadian Geological Survey collection by a specimen from the 

 Upper Devonian limestone of the Hay River section, North West 

 Territory, collected by Mr. E. J. Whittaker. No other example of 

 ripple marks of equally or comparably small wave-length in lime- 

 stone has come under the notice of the author although symmetrical 

 ripple marks of similar wave-length and amplitude in sandstone are 

 very common. 



Miller^ states that small ripple marks with a wave-length of from 

 I to 2 inches and amplitude of \ inch occur at several horizons in the 

 Pamelia, Lowville, and Trenton, but does not indicate whether they 

 are current or oscillation ripples. 



The numerous examples of Palaeozoic limestone ripple marks 

 described by Prosser include both symmetrical and asymmetrical 

 ripples but all are forms with long wave-length, generally from 20 

 to 36 inches. In several cases they are described as "clearly 

 asymmetrical,"^ or with slopes steeper to the west than to the east, 

 thus leaving no question as to their current origin. In other 

 cases Prosser found "no difference in the slope." Udden^ notes 

 limestone ripples which are "slightly unsymmetrical." 



^William J. Miller, "Geology of the Port Ley den Quadrangle, Lewis County, 

 N.Y.," Bull. N.Y. State Mus., No. 135 (1910), p. 36. 



^ Charles S. Prosser, "Ripple Marks in Ohio Limestones," Jour. Geol., Vol. XXIV, 

 No. s (July-August, 1916), p. 459. 



3 J. A. Udden, "Notes on Ripple Marks," ibid., No. 2 (February-March, 1916), 

 p. 125. 



