CORRESPONDENCE. 



The Threefold Division of the Drift. 



In the appreciative review of the late Professor Carvill Lewis's Glacial Geology 

 of Great Britain and Ireland, which appeared in your May number, Professor Lewis 

 is credited with removing, among other stumblmg blocks, that of the supposed 

 threefold division of the drift. "He showed that the old view of the threefold 

 classification of the drift into an upper and a lower boulder clay, separated by 

 sands, is absolutely untenable ; that even within very short distances this supposed 

 sequence is often reversed, and we may get the boulder clay in the middle, with 

 sands above and below." 



Will you permit me to point out that from a very early period of my study 

 of the drift, my observations led me to doubt the correctness of such a classification. 

 In all the Glacial papers published by me since 1873, and they have been pretty 

 numerous, I have contended for the unity of the Glacial Period in Britain, and have 

 stated again and again that the so-called Lower Boulder Clay, Middle Sands and 

 Gravel, and Upper Boulder Clay do not represent two Glacial Periods, divided by 

 an inter-Glacial Period, but are continuous deposits. The arguments quoted from 

 Professor Lewis are such as I have frequently used, and that at a time when I was 

 practically alone in my opinion. Professor Lewis told me personally that he agreed 

 with many of my glacial views, and the evidences of the fact can be seen in the 

 book itself. 



It follows from this that there is a possibility, however remote, of an 

 " orthodo.x " geologist being right, though he may think there is something still to 

 be said in favour of submergence. 



Allow me to add that I have read the work of Professor Lewis, whom I held in 

 esteem, with great interest, and think that his field notes and elucidatory remarks 

 are of very great value, showing extensive and accurate observation put into a form 

 that can be used by any competent geologist, whatever may be his views. What is 

 still more rare, they exhibit an open and truthful mind, that does not blink facts, 

 whichever way they may seem to tend. 



Park Corner, Blundellsands. T. Mellard Reade. 



May I, 1894. 



Mr. William Taylor (Llanbryde, Elgin) writes deprecating the tone of our 

 review of Mr. E. T. Newton's memoir on the Fossil Reptiles of the Elgin Sand- 

 stones {supra, p. 305). He remarks that the Naturalists of Elgin are grateful to Mr. 

 Newton and the Geological Survey for the labour they have bestowed upon the 

 subject, and points out that no unconformity has yet been discovered between the 

 reptiliferous beds and those containing Palaeozoic fishes. He asks, " might not 

 Elginia and Gordonia be Permian?" He then comments upon the lamentably 

 frequent tendency of professionals to ignore the work of local observers, and adds : 

 "We cannot help pointing out that Patrick Duff, of Elgin, was right about the 

 Parallel Roads of Glenroy, while Darwin was wrong. Duff was right in saying that 

 Dendrodus was the tooth of Holoptychius, and Owen was wrong. Professor Judd said 

 that fossil reptiles would not be found south of a certain line of fault : Dr. Gordon, 

 of Elgin, declared they would be so found, and he has proved to be correct." 



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