Mr Hugh Miller on Boidder-Glaciation. 



183 



with but doubtful success. They were made at sections, 

 which, though the best I then had access to, lay too much 

 under the shelter of higher ground. In uplying situations 

 also, where the drift is apt to be a hash of angular fragments 

 in a coarse and scanty matrix, fluxion-structure is generally 

 difficult to detect ; and the same may be said of that top- 

 dressing of raw materials which forms the capping of many 

 good sections. Nor can it be invariably expected even in the 



Fig. 12. 



Contorted Fluxion -structure, Northumberland, representing one square 

 yard horizontal surface. A, Dark Till finely stony ; b, Red Till, stones absent. 



most favourable situations. Fig. 12 represents a contorted 

 fluxion-structure of differently coloured clays kneaded to- 

 gether, which better than any words will explain the reason. 

 It is obvious that a structure of this kind could only be dis- 

 played where the section is unusually clean and the texture 

 unusually fine, and where there has been a warp and woof 

 of distinct boulder-clays to work together. In general, this 

 rolling and kneading would produce nothing but confusion. 

 No student of the till needs to be reminded of the frequency 

 of obscure symptoms of contortion within its mass. 



Orientation hy means of Fhixion- Structure. 



I have only recently made any strict test of the extent 

 to which the direction of ice-movement can be deter- 

 mined from the symptoms of fluxion-structure alone. 



