14 
MUSEUM BULLETIN NO. 25. 
behaviour has been mentioned by John S. Owens 1 and by G. K. 
Gilbert.* These ripple-mark ridges which travel against the 
current are called by Gilbert antidunes, the ordinary current 
ripples which travel with the current being called dunes by him. 
Gilbert recognizes three phases in connexion with the conditions 
governing migrating ripple-mark depending on the stream load. 
“With any progressive change of conditions tending to increase 
the load the dunes eventually disappear and the debris surface 
becomes smooth. The smooth phase is in turn succeeded by a 
second rythmic phase in which a system of hills travel upstream. 
These are called antidunes, and this movement is accomplished 
by erosion on the downstream face and deposition on the up- 
stream face .” 3 The term sand wave has been used frequently 
in Great Britain for the migrating ripple-mark, particularly 
when it is of large size. Some French writers have employed 
the term greve but I prefer the term asymmetrical or current 
ripple-mark. One American author 4 has used the terms “ripples 
of deposition” and “ripples of erosion” corresponding respectively 
to asymmetrical and symmetrical ripple-mark as these terms 
are used in this paper. This nomenclature is based upon 
inferences regarding the respective roles played by the two 
types of ripple-mark which are open to the question and is, therefore 
unsatisfactory. When viewed through water the symmetrical 
and asymmetrical types often can be distinguished only with 
difficulty or not at all. Because of their close resemblance 
the term ripple-mark should, I think, continue to be associated 
with the two types of fluting produced respectively by current 
and wave-action. 
Reference may be made here to a recent paper by Ch. 
Epry* which introduces an explanation of the formation of 
ripple-marks wholly novel and different from the one gener- 
ally accepted. No reference is deemed necessary by this author 
1 London, Geog. Jour., voi. 31, 1908. p. 424. 
* “The transportation of debris by running water," U. S. Geol. Surv., Prof, paper 86, 
1914, p. 31. 
* Ibid. p. 11. 
* Brown, A. P., “The formation of ripple-mar ka, tracks, and trails,” Proc. Assoc. Nat. 
Sc., Philadelphia. LXIII (1911), pp. 536-47. 
* "Annalea de l'lnatitut Oceanographique" (Fondation Albert ler Prince de Monaco) 
Paris, voL 4, pt. 3, 1912, Ann. Rept. Smithsonian Inst, for 1913 (1904), pp. 307-318. 
