480 Correspondence — Mr. Alfred Tijlor. 



that in the Glacial period they seemed to have been accompanied by 

 subsidence, and that Greenland appeared to be sinking at the present 

 day under its ice-cap. On the 21st June of this year, Mr. T. F. 

 Jamieson, F.G.S.,' read a paper before the Geological Society, the 

 published abstract of which represents his view of the subject to be 

 "that the depression of the land was caused by the weight of ice 

 laid upon it, and the re-elevation by the disappearance of the ice." 

 I do not know whether Mr. Jamieson claimed complete originality 

 for his hypothesis, but in any case the evidence collected by him 

 must be of great value and is very welcome. 



J. Starkie Gardner. 



GREAT POST-GLACIAL FLOODS AND THE PLUVIAL PERIOD. 



Sir, — In reference to Mr. H. H. Howorth's statement (see Geol. 

 Mag. Sept. p. 417) that Mr. Belt urged that these Floods (Gravel- 

 Period) were caused by the pounding back of the European rivers, 

 and the consequent formation of a European lake by a Great 

 Atlantic Glacier (see Thomas Belt's papers, Quarterly Journ. of 

 Science, No. 44, Oct. 1874, and July, 1878, pp. 316-360), I may 

 observe that (in the Quart. Journ. Geol. Soc. 1868, vol. xxv. p. 10) 

 I had previously stated that, " the gorging of ice at the mouth of the 

 Thames, Seine, and Somme, may have assisted in the production of 

 some of the remarkable gravel-beds in these rivers." 



With regard to Mr. Howorth's criticisms on the uniform motion 

 of rivers (op. cit. p. 419), I may observe that if the water in a 

 navigable river did not tend not only to a uniform mean motion, 

 but to uniform maximum and minimum motion in the respective 

 parts of its channel, floods or short water would ensue. 



I particularly excepted the case of floods, because they occur 

 whenever the motion of the stream at any part deviates by excess 

 from its uniform mean motion. If Mr. Howorth will refer to my 

 paper in the Phil. Mag. 1853, pp. 258-274, he will find that I 

 have particularly noticed the inequality of the current in rivers, and 

 show that the origin of horse-shoe bends is attributable to inequalities 

 of rainfall, and of speed of the water in different parts of its channel. 



From Mr. Howorth's criticisms of the various opinions, explana- 

 tions and theories of Sir Charles Lyell, Messrs. Prestwich, S. V. 

 Wood, T. Belt, Croll, myself, and others, I conclude that the ex- 

 planations of these geologists all fail to satisfy him ; nevertheless he 

 is ready with a theory of his own, calculated to meet all the difficul- 

 ties of the student of Quaternary Geology. This, so far as I am 

 able to comprehend it, is a modification of, but far transcends the 

 wildest speculation of M. Adhemar. 



Alfred Tylor. 

 Shepley House, Carshalton, Surrey, 

 Sept. \Uh, 1882. 



1 See the Ml text of Mr. Jamieson's paper, Geol. Mag. Sept. and Oct. 1882, 

 pp. 400 and 457.— Edit. Geol. Mag. 



