798 SoLLAS — A Map to show the Distribution of Eskers in Ireland. 



inference from the facts observed. Thus far but few signs of sub-glacial streams 

 have been recognised far back from the coast. Near the coast there are some 

 evident signs of such streams, and some kames may have been deposited by them." 

 — [Ibid., p. 516). 



A study of the eskers of Connecticut Valley by Professor Dana* led him to 

 doubt whether they were genuine eskers, and to contend that they are merely 

 coarser parts of a system of alluvial terraces. 



A theory, which has at least the merit of novelty, was proposed by Professor 

 Shaler in 1884.t It will be readily understood from the following short citation : — 

 "This association of kames with drift deposits formed beneath the surface of 

 water, long ago led me to the hypothesis that the ordinary kames are structures 

 that were made beneath the surface of water-covered regions, and that they accu- 

 mulated at the points where subglacial rivers discharged their streams beneath 

 the ice into the sea, or the temporary lakes that abounded over the land-surface 

 during the glacial period." Subsequent investigation has, however, led him to 

 relinquish this explanation. 



An interesting Paper was read before the British Association in 1884 by Pro- 

 fessor Carvill Lewis. J It contains a general account of eskers, of the literature 

 of the subject, and of proposed explanations. The author agrees that either they 

 " must have been enclosed within high walls of ice, or the streams of water which 

 formed them must have flowed in subglacial tunnels." The direct object of the 

 paper is the description of certain eskers in Pennsylvania, which stand in close con- 

 nection with the great terminal moraine, being sometimes continuous with it; 

 they are all short, from a few hundred feet to a few miles in length, and they slope 

 downwards towards a river valley, or other watercourse, in the ojjposite direction 

 to the movement of the once overlying ice. Professor Lewis consequently concludes 

 that they were formed by a backward sub-glacial drainage. 



Professor Winchell,§ after describing an important esker, which he names the 

 Bridgewater kame, gives a long series of important conclusions which he thinks 

 may be drawn from it. Briefly summarised, these are that the esker was formed 

 by an existing river, " Straight River," at a time when its waters flowed over the 

 upper surface of a glacier. 



Kames are described as occurring in Canada by Mr. R. W. Ells and Mr. R. 

 Chalmers.|| Both of these observers call attention to the resemblance in the course 



* The Kames of Connecticut Valley, by J. D. Dana. — Amer. Joum. Sci., vol. xxii., 1881 (1882). 

 f On the Origin of Kames, by N. S. Shaler. — Proc. Boston Soc. Nat. Hist., vol. xxiii., p. 36, 1884. 

 \ On Marginal Kames, by H. Carvill Lewis. — Proc. Acad. Nat. Sci. Philadelphia, 1885, p. 157. 

 § The Geology of Minnesota. — Final Report, vol. i., 1884, p. 665. 

 II 6eol. Survey of Canada, 1885, p. 65 E. and 28 GG. 



