‘ 
420 Messrs. W. Phillips and S. Woods on the [Dec. 
Close to the Devil’s Bridge, on the side beyond the Inn, there 
is a quarry of slates, of which the cleavage runs as usual NE 
and SW, dipping towards the NW at 50°; but on the northern 
side the rock immediately adjoining the bridge, the dip and 
direction are very different. It is, however, manifest that this 
mass, part of which forms the abutment of the bridge, is not 
in situ, since its seams are opened, and the rock itselfappears to 
have been shattered in its fall. In the deep ravines of the sin- 
gular scenery opposite to the Inn, we anticipated an opportunity 
of ascertaining the nature of the rocks of this place. On 
descending these ravines to view the fine waterfalls beneath the 
bridge, we found the dip and direction agree uniformly with 
those of the quarry above-mentioned. We afterwards went to 
see the grounds belonging to that boast of all the tourists, 
Hafod, and on the banks of the Ystwith, traversing its beautiful 
valley (in which it appeared to us that art had done much, but 
nnture more), we had numerous opportunities of ascertaining 
that the dip and direction of the slates agree with those near the 
Devil’s Bridge. In both places, the slates still continued to 
enclose layers ofa granular rock resembling that so often noticed. 
Occasionally also, it occurs in blocks and kernels, and is so 
soft as to yield easily to the knife, and in several instances was 
observed to decompose in the same cellular manner as some of 
the chloritic slates of the summit of Snowdon and other places, 
the cells, however, being much smaller. Near the bridge at the 
termination of the Hafod grounds on the road to Tregarrow, 
were some large masses of slate enclosing layers of the rock in 
question, parts of which were so far ie pn as readily to 
break down into a perfectly soft substance of an ochreous-brown 
colour. Hitherto, therefore, the slates and slaty rocks appear to 
partake largely of the characters of those forming the more 
mountainous regions of the most northern parts of Wales; and 
it may be observed that hitherto we have not seen a single 
‘rock bearing in any degree the character of greywacke. 
Between Hafod and the Devil’s Bridge, the country continues, 
as between the latter place and Hafod, bold, but extremely ste- 
rile, the lofty hills being so completely covered by coarse ver- 
dure to their summits, that the rock is visible chiefly along the 
-water-courses in the bottoms of the valleys. Few trees, and as 
-few attempts at cultivation, are visible on the sides of the road. 
Slates enclosing masses and layers of the same varieties as those 
-prevailing between Machynlleth and the Devil’s Bridge are occa- 
sionally to be observed, and possessing the same line of bearing. 
Just before arriving at Rhyader, however, the character of the 
country became changed : the hills surrounding that place are 
lower, and have rounder summits than any that we have pre- 
-viously observed; while the broader valleys offered the 
reverse of the picture we had so lately seen, being well culti- 
vated and wooded. We now turn into the valley of the Wye, and 
