353 
Lithological Survey of Schehallien. 
to be met with, except toward the base of the mountain, where 
it is sometimes greater, and is subject to considerable inequa- 
lities. The strata on the north side of the mountain lean a 
little toward the north, and those on the south toward the 
south. All these variations, however, are inconsiderable, and 
in general the strata may be set down as nearly vertical. 
But though in their disposition all the rocks of Schehallien 
agree pretty nearly, they differ considerably in their mine- 
ralogical characters. A large proportion of the mountain, and 
that which constitutes the most elevated part, is formed of a 
granular quartz, extremely hard, compact, and homogeneous. 
The whole mass from about the level of the two observa- 
tories up to the summit of the mountain, is of this stone. 
Lower down, again, on every side, the rock is a schistus con- 
taining much mica and hornblend ; and the division into paral- 
lel and vertical plates is more obvious than in the granular 
quartz. This last, however, is sometimes found in the lower 
parts, forming thin, vertical plates, interstratified with the 
hornblend and mica slate, and all together preserving their 
parallelism with a neatness and accuracy which a work of art 
could hardly exceed. This is particularly to be observed in 
the bed of the bum of Glen more, the stream that defines the 
base of the mountain on the south, and which toward the lowef 
part of its course intersects the strata to a great depth. 
Besides these two kinds of rock, we meet in several places 
toward the base of the mountain with a granular and mica- 
ceous limestone highly cristallized, which in one or two places 
ascends to a considerable height. All these rocks are disposed 
in strata ; but there are also veins or dykes of porphyry and 
greenstein, which traverse the mountain in different directions; 
MDCCCXI. 
