G^RfeAT GLEN OF SCOTLAND. 
19^ 
quently cuts across the line of the sandstone chain, and 
falls into the sea two miles behind Craig Phadric. 
It is in a quarry in this direction, opened, near the vil- 
lage of Clachnaharry, for the use of the Caledonian Canal, 
that the rare and beautiful mineral foliated celestine occurs. 
It is found in the sandstone^ in minute detached crystals, 
sind in veins^ and sometimes associated with calcareous spar« 
Having thus noticed the general extent of country occu- 
pied by the red sandstoncj it is now necessary to enter a 
little more particularly into its composition. 
This red sandstone consists of minute particles of quartz, 
and a few scales of mica, either simply attached to each 
other, or connected by a basis of red, seemingly decom- 
posed, felspar. Its coarser varieties forfti a conglomerate, 
which consists of pieces, both round and angular, of gra- 
nite, gneiss, mica-slate, felspar, and common quartz, the 
whole being cemented by a hard basis of quartz. In many 
places the rocks are so exposed, that the transition from 
the coarse conglomerate into the fine sandstone can be easi- 
ly traced ; and when this is the case, the transition either 
takes place by a gradual diminution of the particles of the 
conglomerate, thereby passing into the sandstone, or by an 
alternation of successive layers of coarse and fine stone. 
Even sections of the same stratum or layer will deve- 
lope these transitions. Sometimes one part of the mass 
will be of fine sandstone, and the rest of conglomerate, or 
unconnected portions of the conglomerate will be found 
completely inclosed in the sandstone. Frequently an im- 
mediate passage can be discerned from the coarsest conglo- 
merate to the finest sandstone, and then the larger frag- 
ments appear sticking in the sandstone, as if they had been 
wedged into it. In regard to the position of these two 
substances, I have observed, that, although the sandstone 
and conglomerate frequently alternate with each other, the 
K 2 
