136 Correspondence — Prof. A. C. Ramsay. 



Saccammina lias been found in the forthcoming Monograph on Car- 

 boniferous and Permian Foraminifera by my friend Mr. H. B. 

 Brady, F.K.S., he himself will be surprised at their number. 



College of Physical Science, G. A. Lebouk. 



Newcastle-on-Tyne, 9 Jan., 1876. 



THE OEIGIISr OF LAKE BASINS. 



Sir, — It is not my intention to reply to the detailed arguments 

 produced by Mr. Judd in his attempt to prove that my theory '• on 

 the glacial origin of certain Lakes " is untenable by persons having 

 an accurate knowledge of ordinary physical geological phenomena. 

 Were I to do so, I should have to repeat old arguments used by me 

 in reply to the objections long ago raised by the late Sir R. Murchi- 

 son and Sir Charles Lyell, objections very similar to those used by 

 Mr. Judd, and which seemed to me and others easily disposed of. 

 If any one cares to look into that early history of the subject, he 

 will find these replies in the volumes of the PhilosojpJiical Magazine 

 for 1864 and 1865. To other objectors I paid no attention, partly 

 because the late Professor Jukes and others, of their own accord, 

 did it perfectly well for me, and partly because I can generally em- 

 ploy my time better than in geological controversy. 



Two or three points, however, I will notice. 



In the first place, from anything that appears in Mr. Judd's paper, 

 the reader might suppose that I attributed the formation of all rock- 

 bound lake-basins to the action of glaciers, in spite of a statement, in 

 a note to the original memoir, that " many lie in craters of extinct 

 volcanos, some, no doubt, in areas of special subsidence, and others 

 may be due to causes of which I know nothing." In the same 

 memoir I also in several places insist on the occurrence of moraine- 

 dammed lakes, and also speak of others dammed up by irregular 

 accumulation of the original drifts of the Glacial epoch. 



The same facts are again insisted on in my " Physical Geology and 

 Geography of Great Britain," with the addition of lakes dammed by 

 eskars ; and besides, to prevent all misconception, I mentioned the 

 African lakes, alluded to by Mr. Judd, as probably, in my opinion, 

 like the Caspian, being parts of old sea-bottoms. I should certainly 

 never have been so wild as to attribute the hollow of the Dead Sea to 

 glacial erosion, though Mr. Judd seems to think that some persons 

 may do so, confining myself as I did, and do, to the " origin of 

 certain lakes " in well-recognized glaciated regions. 



Secondly, it seems strange to me that Mr. Judd should have selected 

 Lake Balaton as a crucial test to the theory of ice erosion. I never 

 knew any one who denied the well-known fact that lakes may be and 

 have been formed by subsidence in volcanic areas. I have seen 

 examj^les of such, and have read of and believed in many others, both 

 in Europe and America. Earthquake shocks have also been known 

 to produce changes of level that gave origin to lakes, and ordinary 

 landslips do the same. That there are great areas of inland drainage 

 full of salt lakes, some of them below the level of the sea, is another 

 piece of popular knowledge, and I never heard of any one who 

 attributed all of these hollows to glacial erosion. 



