416 Messrs. W. Phillips and S. Woods on the . [Dzc, 
(/_ 
TL = 
PALL 
We afterwards traversed in our, way to Harlech, a country 
consisting of the usual rocks and slates, possessing but little 
vegetation for some miles. Quartz often prevailed so greatly in 
the rock as to give it a character approaching to that of quartz 
rock. The precipice overhanging Llyn Tegwin, which is very 
lofty and unusually rugged, consists chiefly of slates presenting 
arhombic form, probably from weathering, the acute angles of 
the monstrous rhombs protruding from the face of the precipice. 
Two layers of considerable thickness of the usual rock were 
interstratified parallel to the cleavage plane of the slates, the 
one near the summit, the other at the base; they appeared 
parallel, the direction of the latter being towards the north-west 
at an angle of 30°, being a much lower angle than we had before 
seen. 
At about the distance of four miles from Harlech, and while 
traversing a valley chiefly, if not altogether, of slates more than 
usually brittle, and apparently ina state of decomposition, and 
admitting of the growth of considerable woods of small oaks, 
we perceived on our right hand two lofty hills, each presenting 
to us a rugged scarp, consisting of slates, having precisely the 
same appearance as those overhanging Llyn Toaveidl and 
crowned, one of them in a remarkable manner, by rocks in the 
form of closely aggregated columns, of the height, as well as we 
could judge from below, of 30 to 40 feet. These rocks dip to 
the NW, and though we had no opportunity of inspecting them, 
we inferred from what has been described as occurring in the 
ample basin of Rhydr Dha, that they did not differ from the 
usual rocks of the district. 
The long ridge, at the southern termination of which Harlech 
Castle stands, and which presents its side towards the sea, 
consists, in its upper beds, of a coarse slaty rock manifestly 
appertaining to the rock so constantly observed, of which its 
lower beds consisted; quartz, however, prevailing in it ina more 
than common degree. 
