3 ° 
SCENERY OF SWITZERLAND. 
Granite, like Gneiss, must have solidified under 
considerable pressure, and therefore at a great depth. 
In the first place, the crystals it contains could not 
have been formed unless the process of cooling had 
been very slow. In addition to this, they present a 
great number of minute cavities containing water, 
liquefied carbonic acid, and other volatile substances. 
Sorby, whose main conclusions have since been 
verified by others, has endeavoured to calculate what 
must have been the pressure under which Granite 
solidified, by measuring the amount of contraction in 
the liquids which have been there imprisoned. He 
considered that the Granites which he examined 
must have consolidated under pressure equivalent to 
that of from 30,000 to 80,000 feet of rock. The 
more superficial layers probably resembled Basalt. 
Serpentine. 
Serpentine is a compact or finely granular rock, 
olive-green, brown, yellow, or red, and has a more 
or less silky lustre. There has been much doubt as 
to its origin, but it is now regarded generally as an 
altered igneous rock. 
Crystalline Schists. 
Over the Gneiss lie immense masses of Crys- 
talline Schists, s.everal thousand feet in thickness. 
