AND QUARTZ DEPOSITS OF ASSYNT. 349 
M’Culloch estimates the thickness of the Old Red of the west 
coast, in his description of the hills scooped out of it by the 
denuding agencies, at from one to three thousand feet. 
Above the Red Sandstone there occurs a bed of quartz rock, 
several hundred feet in thickness, which bears in some of its 
layers a pure white, in others a flesh-colored tint. It is a 
stratified rock, but less regularly so than the sandstone which 
it overlies ; and, though hard, splinty, and indestructible in all 
its strata, it is decidedly mechanical in its composition. This 
indurated deposit must have at one time existed as a quartzose 
sand, — at another as an ordinary sandstone. Its upper strata 
are of a red color, mottled with white; and in one of these the 
white portions take the form of minute cylinders, vertically 
arranged across the stratum, like jars in acase. Where ex- 
posed to the weather, the red parts of the stone waste from 
around these, leaving them standing up over the surface, as the 
little pipes in the cistern of a shower-bath stand up over the 
plane of the bottom; and these curiously relieved cylinders 
M’Culloch regarded as probably organic. I could, however, 
find no grounds whatever for the conclusion, as in their me- 
chanical structure they differ in no respect from the red matrix 
which incloses them. They serve, however, to remind one of 
similar appearances in the Old Red Sandstone of the east coast. 
This bed of quartz rock forms some of the more picturesque 
mountains of Assynt. Seen from the inn at Inch-na-damph, 
the tall hill of Spike-an-Quenaig, which is entirely composed 
of it, is one of the most remarkable in a landscape which, for 
the bold grace of its features, is scarcely surpassed in Scotland. 
An outline of flowing curvature divests it of the stiffness neces- 
sarily associated with the perfectly conical form. It swells 
slightly outwards where the architect would place his cornice, 
and then terminates in a horizontal table of small extent, re- 
sembling the plane of a pedestal. The entire hill is in truth a 
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