Correspondence — Dr. G. Linnarsson. 287 



the embayed outcrops abreast of tbe features on either hand, the basin 

 is filled up, and the pre-existent surface approximately restored. 



I believe that these are not isolated cases of rock-basins demon- 

 strably eroded. Semerwater, in Yorkshire, which may be considered 

 as an outlier of the Lake District proper, is seemingly bounded by 

 strata nearly horizontal and obviously undisturbed, and might well 

 form a link between the small Northumberland lakes and those 

 larger basins of the origin of which no stratigraphical evidence 

 seems obtainable. 



The comparative infrequence of sharp synclinals even in some 

 rocks of great age seems to militate strongly against the subsidence 

 theory of lakes. The extraordinary regularity of the Cambrian 

 Sandstones of the western districts of Eoss and Sutherland I believe 

 to be quite irreconcilable with the great numbers of rock-basins in 

 these regions on any theory save that of erosion. From Suilven 

 more than 200 lakes and tarns can be counted, yet the present 

 surface is but one of many that may have existed during the progress 

 of that denudation of which Mr. Judd's Scottish researches so 

 eloquently tell. If the movements in the crust had been half as 

 rife in past geological ages as Mr. Judd's views of lake formation 

 require for the recent one, the Cambrians could scarcely have shown 

 a uniform dip for ten yards together. 



In conclusion, rock -basins I believe may be ranged under three 

 heads. 1. Those demonstrably due to subterranean movements. 

 2. Those demonstrably due to erosion. 3. A large number of 

 which the origin is, and in some cases may always remain, doubtful. 



Wark-on-Tyne, Hugh Miller, 



Maij 6th, 1876. H.M. Geol. Survey of England and Wales. 



OLDEST FOSSILIFEEOUS EOCKS OF NOETHEEN" EUEOPE. 



giR^ — In a letter inserted in the May Number of the Geological 

 Magazine, Mr. Hicks makes some objections to my paper on the 

 Oldest Fossiliferous Eocks of Northern Europe in the April Number. 

 There are especially two points in which Mr. Hicks thinks that my 

 views are incorrect and endeavours to corroborate his own. 



Firstly, Mr. Hicks attempts to demonstrate that the Swedish area 

 cannot have been depressed at as early a period as the British, by 

 reasoning as follows : The Cambrian and Lower Silurian rocks of 

 Sweden have an average thickness of 1000 ft., while the British are 

 30,000 ft. in thickness ; there is no reason why the Swedish area 

 should not have been depressed at the same rate as the British ; the 

 lowest Swedish beds must, therefore, be younger than the lowest 

 British, for, if that be not the case, we must suppose that before the 

 close of the Lower Silurian period the Swedish sediments were 

 deposited in a depth of 29,000 ft. of water, which is impossible, as 

 the characters of the faunas indicate very similar conditions in the 

 British and Swedish areas. If we draw the full logical consequences 

 of this Mr. Hicks' reasoning, we come of necessity to the conclu- 

 sion that all the strata which we have in Sweden been used to refer 



