vm.. xtx. ( 2 ) THE SILURIAN INLIliR OF USK 
145 
(3) The fossils from the Ludlow beds near the margin of 
the Inlier are not those which characterise the uppermost beds 
of the Coed-y-paen Inlier. 
(4) Nowhere along this Eastern boundary has the yellow 
quartzose sandstone, which forms the base of the Old Red 
Sandstone, been observed, although in the road from Llandeg- 
veth to Llangibby and close to Little Hill Farm, Old Red 
Sandstone is to be seen within a very few feet of the Silurian 
beds. 
In the region of Pen-y-parc the Anticline has a small 
syncline at its summit (see fig. 4), and in it a small patch 
of Old Red Sandstone has been preserved. There are two 
ponds near the house which show red soil in their deep banks, 
and though no actual exposure of rock is now to be seen, the 
Survey map is no doubt right in representing a small area of 
Old Red Sandstone close to the house. 
N.W. S.E. 
Pen'-y-parc 
Fig. 4. — Section through the Llangibl>y Anticline, near Pen-y-parc. 
Horiz. : .Scale about .ps" = i mile. Vert : Scale i" = 800 ft. 
About half ii mile to the West, Old Red Sandstone is 
again suggested by the colour of the soil, and is seen in situ in 
the bed of a small stream, where it dips 27° W. S. W. As five 
yards lower down the stream, Ludlow beds occur, dipping 
10° S. W., the two sets of beds are probably separated here 
by a fault. 
Some half a mile to tlie North of Pen-y-parc the Llangibby 
.\nticline is cut across by a fault, which shifts the crest of the 
Anticline on its Northern side to the East, the crest running 
under the old Castle in a slightly sinuous line to Cwm Dowlais, 
where the base of the Ludlow beds is reached, and an arch of 
Wenlock Limestone exposed. 
L2 
