A. R. Hunt — Nomenclature of Ripple-mark. 417 



references to the papers of Messrs. Sorby, De Candolle, Forel, and 

 Darwin. To these I would add the shrewd observations of that 

 king among observei's, De la Beche, in his " Geological Observer," 

 and several papers by Dr. Vaughan Cornish in the publications of 

 the Geographical Society which have appeared since I retired from 

 the fray. 



In May, 1903, 1 concluded a paper on Vein Quartz with a quotation 

 from a letter written by Dr. Sorby in 1889 — "There are many 

 things connected with it [granite] about which we know much less 

 than is desirable." Let me conclude this paper with the last few 

 lines of the same author's 1859 paper on the " Structures produced 

 by Currents " : " Those [experiments] which I have made already, 

 though not nearly sufficient to clear up many highly important 

 questions, are still sufficient to give very great encouragement ; 

 and I therefore feel anxious to induce others to turn their attention 

 to this branch of research, being convinced that it cannot but yield 

 a bountiful harvest of fact when studied with perseverance and 

 zeal." To this conviction, now forty-five years old, we may still 

 add our fervent Amens. 



P.S. — Since the above was written, I received, on the 1st of July, 

 Nature for June 30th, and Dr. Nansen's " Bathymetrical Features 

 of the North Polar Seas," etc. Dr. Nansen observes (p. 137), 

 " ripple-marks, however, are not merely formed by waves, but also by 

 currents." Nature, referring to experiments made by Mr. F. Ayrton 

 at the Royal Society conversazione, asserts, with the emphasis of 

 italics, " It was also shown that ripples are not produced by a steady 

 current of water flowing over sand." Dr. Vaughan Cornish writes : 

 " The true current-formed sand-wave I find to be produced as soon 

 as the velocity of the stream causes the water to be turbid with 

 a heavy charge of sand in eddying suspension. The process can 

 be watched in the shallow streams of sandy tidal foreshores " 

 (Geographical Journal, August, 1901, p. 198). I have noticed this 

 result myself. 



In the same paper (p. 200) Dr. Cornish writes, " Professor Osborne 

 Reynolds found that in his model estuaries the ripples ' formed by 

 the alternating action of the tide ' had a wave-length equal to twelve 

 times their amplitude (4 = 12 H)." 



If Professor Reynolds used the terms wave-length and amplitude 

 I should have to retire discomfited, as I had the honour to serve 

 on his committee ; but I find that what Professor Reynolds wrote 

 was, " Some of the ripples were from hollow to crest as much as 

 one-fourth the mean-rise of the tide, the distance between them 

 being twelve times their height" (Rep. Brit. Assoc, 1889, p. 343). 

 Professor Reynolds avoids the technical wave terms. 



The apparent contradictions of writers on ripple-mark are so 

 surprising that one fails to see how the student, or even the text- 

 book writer, can find his way through the mist. However, the 

 contradictions are easily explained, as there are several ways of 

 producing rippled sand-surfaces. If not trespassing too much on 



