COURSE OF VEINED STRUCTURE MOTION OF GLACIERS. 247 



dip of the laminae at the loop of the horizontal curves, which in 

 the upper region of the glacier is nearly vertical, gradually slopes 

 forwards, until, at the lower termination, it has a very slight dip 

 inwards, or, indeed, may be reversed, and fall outwards and 

 forwards. The general form of a structural lamina of a glacier 

 rudely resembles that of a spoon. 



This structure and the accompanying dirt-bands have been 

 recognised by different observers in almost all glaciers, including 

 those of Norway and of India. The interval between the dirt- 

 bands has been shown in the case of the Mer de Glace (and 

 therefore probably in other cases) to coincide with annual rate 

 of progression, and in the higher parts of the glacier (towards the 

 neve) to be accompanied by wrinkles or inequalities of the sur- 

 face, which are well marked by the snow lying in them during 

 the period of its partial disappearance.* 



The Motion of Glaciers, and its causes. The most charac- 

 teristic and remarkable feature of glaciers is their motion down- 



wards from the neve towards the lower valley. The explanation 



* Fifth Letter on Glaciers. Edinburgh Philosophical Journal, 1844 [reprinted 

 in the present volume] ; and Travels in the}Alps, 2d edit. 



