134 Corresjjondence — Mr. Howorth. 



while he asserts that their conclusions are wrong, he ignores the 

 evidence they produce, such as the invasion of one area by boulders 

 from another, and the gradual decrease in the number of the 

 boulders as they recede from their parent source. 



I had not sufficient time to search for numerous instances of strise ; 

 but so far as the disposal of the stones are concerned, I can corrobo- 

 rate Messrs. Peach and Home's observations in the greater part of 

 Northmavine ; and see no escape from the conclusion that, to the 

 north-west of Hillswick, the ice-sheet flowed from the S.E. to N.W., 

 while further south, and on the east side of the island, the direction 

 was from north-east to south-west. Thomas Stewart. 



Watee, Works, Glasgow, 14th. Bee. 1881. 



MR. HOWORTH' S REPLY TO MR. REID. 

 SiK, — In his former note Mr. Eeid spoke of the theory of violent 

 changes as extinct. To this I replied that in calling it extinct he 

 must have overlooked the weighty opinion of Continental geologists. 

 Mr. Eeid now confesses that he did so, and that he was merely 

 speaking of geologists on this side of the Channel, and he proceeds 

 to justify his limitation by a sweeping depreciation of recent Con- 

 tinental writers on Post-Glacial geology. It certainly seems extra- 

 ordinary that such an experienced and deservedly widely-known 

 observer as Mr. Eeid should permit himself to write thus in your 

 widely-circulated pages, I hope I have as great a respect for the 

 magnificent work done by Mr. Prestwich and those who have 

 succeeded him as any one ; but I must confess, and others will 

 assuredly echo my words, that, judged by the abundance of its facts, 

 the careful sifting of its evidence, and the brilliant character of its 

 induction, no work produced on this side of the Channel, in recent 

 years, dealing with Post-Glacial geology, can compare with M. Bel- 

 grand's magnum opus on the Seine Valley ; while it is literally in- 

 credible how any one who has read any considerable number of the 

 memoirs which have seen the light in recent years in France, Bel- 

 gium and Italy, dealing with this very difficult period, can speak of 

 them as in any way inferior to the contemporary writings of English 

 geologists. They far exceed in number and in minuteness of treat- 

 ment similar memoirs written here, for the very good reason that 

 the people whose interest in these deposits has been excited by the 

 discovery of remains of Paleolithic man in them is very much in 

 excess there of what it is here. Leaving, however, this debateable 

 land, where rival national reputations are necessarily weighed in a 

 very uncertain balance, what is to be said of what follows? Mr. 

 Eeid tells us that " In most jDarts of the Continent the Pleistocene 

 deposits appear to be represented by one tolerably uniform mass, 

 like the Loess of the Ehine, or the Tundras of Siberia." Is this so ? 

 I was under the impression that the number and variety of the so- 

 called Pleistocene beds in France and Southern Eussia should be 

 described by any adjective rather than uniform,. Having postulated 

 this, Mr. Eeid contrasts the deposits on the Continent with the 

 wonderful variety of the beds in Britain, their fossiliferous character, 



