79 
Museum Bulletin No. 25. 
Plate XII. 
A. Asymmetrical ripple-mark of irregular pattern, Kingsport, N.S. (Page 12.) 
m 
B. Asymmetrical ripple-mark interrupted by small boulders; estuary at low 
tide of Columbia river near Ilwaco, Washington. Photograph by 
G. K. Gilbert, U.S.G.S. (Page 12.) 
