^84 DOMAIN III. ARGILLACEOUS. 



rally diffused of this kind, may rather pretend to 

 the latter denomination, as where the pebbles 

 are large, they are commonly interspersed at 

 considerable distances. 



STRUCTURE I. LARGE-GRAINED ARGILLACEOUS GLU- 

 TENITE. 



inanects. The most remarkable rock of this kind is that 

 described by Saussure, who discovered it unex- 

 pectedly in a vertical situation, in the Alps of 

 Vaiorsine. In 1776, and afterwards in 1784, he 

 visited the mountain of Balme, which gives source 

 to the river Arve, and made the following curious 

 observations, which chiefly contributed to lead to 

 his system of refoulemcnts or subversions, an idea 

 which unhappily he does not explain at full length, 

 but implying that the rocks now found vertical 

 were formed in a horizontal position, and were 

 afterwards elevated by some cause operating in a 

 contrary direction from beneath or above *. 



" The base of this mountain is a genuine grey 

 granite, with grains of a middling size, and of a 

 structure nothing remarkable. But above these 

 granites are found schistose rocks of quartz, mica, 

 and felspar ; an intermediate kind of rock between 



* The French of the Swiss writers in general is impure, and 

 sometimes requires a particular dictionary, as they think in Swiss or 

 German. 



