113 
Museum Bulletin No. 25. 
Plate XXIX. 
Asymmetrical ripple-mark crossed by miniature ripple-mark due to waves 
transverse to the direction of current, Red beds, Muddy creek, 
Shoshone reservation, U.S.A. Photograph by N. H. Darton, 
U.S.G.S. (Pages 30, 53.) 
