1792. antigutties in Scotland. 133 
It deserves to be remarked, that these different 
erusts or strata, as I] have named them, for want of a 
more appropriated term, do not consist of sepa- 
rate walls, disjoined from one another, but are parts 
of one aggregate mafs; as it frequently happens 
that one stone has one end of it immersed among 
the vitrified matter in the wall, and the other end 
of it only scorched by heat; and in the same 
manner it often happens, that one end of a stone is. 
scorched by heat, while the other end ‘appears never 
to have suffered in the smallest degree from the ac- 
tion of the fire. This affords the clearest proof that 
the heat has been’ applied to them after they have 
been placed in the wall. 
In carrying the section acrofs the level area in the 
middle of the fortification, there was foung a stratum: 
of black vegetable mold B, lying above the solid tock 
CCC. This mold has probably been formed in the 
course of ages by the dunging of fheep which resort 
often to this place for fhelter. 
Nothing seems to be more judicious or simple than 
this mode of fortification adopted by our forefathers. 
The stones for forming the walls were probably dug 
from the top of the rock that formed the ridge of the 
hill, and therefore served at once to level the area of 
the fort, and to erect the mafsy wails without any 
expence of carriage. The walls too, although rude 
‘in form, and inelegant in appearance, were extreme- 
ly well adapted for the only mode of defence that 
their situation rendered necefsary. For as they were 
_always placed upon the brink of a precipice, no wea- 
pon could have been so destructive to an afsailant as 
a stone rolled down the bill; But as the inside of the 
