108 
SILUKIA. 
[Chap. VI. 
In tracing the strata southwards along this axis, other masses of lime- 
stone, more or less amorphous, are seen near Old Radnor, which, in pro- 
portion as they approach the eruptive masses of Stanner and Hanter Rocks, 
and Worsel Hill, or the highly metamorphosed rock of Old Radnor and Yat 
Hill, are themselves subcrystalline, and imbedded, with coatings of serpen- 
tine upon the surfaces of the joints. On the contrary, in receding west- 
wards from that line of eruption and metamorphism, into the Yale of Rad- 
nor, to the south-east of Harpton Court *, the limestone begins to resume 
its bedded character, resting on the Llandovery conglomerates which range 
by Old Radnor church and Yat Hill. Whilst the following section, taken 
from one of the coloured sections of the Government Survey, exhibits the 
syenite and greenstone of Hanter Hill throwing off the Ludlow rocks to 
the south-east, it is also suggestive of the belief that another body of ig- 
neous rock lies subjacent to the conglomerate and crystalline limestone of 
Old Radnor and Yat Hill, where the coatings of serpentine and brecciated 
and altered features of the stratified rocks are, in the eye of the geologist, 
conclusive evidences in favour of such relations. 
N.W. Yat Hill. Hanter Hill. S.E. 
d 1 d* 
e. Ludlow rocks, d". Wenlock shale, d 1 . Woolhope or Lower Wenlock limestone 
(partially altered, with serpentine faces), c. Upper Llandovery, in parts altered. 
* Eruptive rocks (syenite, greenstone, and hypersthene rock). 
The eruptive rocks of this tract are highly picturesque ; and as they offer, 
in a very small compass, phenomena which characterize large mountain- 
masses, a sketch of them is annexed. The spectator is placed at the south- 
eastern foot of Stanner Rocks, near Kington, which are charged with hy- 
persthene : this mineral, though common in some foreign countries, and 
abounding at Loch Scavig, in Skye, has hitherto been found in one other 
British locality only. 
The greater expansion of the Lower Wenlock or Woolhope limestone in 
Radnorshire, as compared with that of the few nodular strata of the same 
age in Shropshire, must doubtless have been in great measure due to the 
larger amount of the original calcareous deposit, the nature of which is still 
visible in the old quarries near Presteign. The amorphous, massive, and 
crystalline condition, however, of the same rock at Nash Scar and Old 
Radnor, was, we cannot doubt, caused by the action of heat issuing along 
a line of fissure, which, emitting the igneous rocks of Stanner, Worsel, and 
* The seat of my esteemed friends the late Sir gratification. The accomplished father passed 
T. Frankland Lewis, and his eminent son, the late away when somewhat ripe in years ; and the fame 
Sir George Cornewall Lewis : the latter first urged of the illustrious statesman, who was taken from 
me to put together all my geological records of us in the summer of his days, is commemorated 
this region, and form the work called the ' Silu- by a monument at New Kadnor in the heart of 
ri in System.' The many happy days I passed in the Silurian Kegion. 
their company are remembered by me with true 
