VOI.. XIX. (2) 
THE SILURIAN' INLIICR OF USK 
55 
The probable explanation of this is seen by referring to 
the map, where the Northern part of the Inlier is represented 
as being displaced Westwards along the fault line mentioned 
above. In the southern part of the Inlier yellow sandstones 
are seen by the roadside to the North-West of the Church, and 
an old pit to the South of the Church was, no doubt, formerly 
used for the extraction of Silurian sandstone, but it is now 
entirely covered by grass. 
The colour and nature of the soil in the fields near here 
also point to the extension of the Silurian rocks to the South 
of the Church, but no exposures are to be seen. 
The appearance of the Ludlow beds in these small inliers 
and the nature of their fossils, points to their corresponding 
to the topmost beds of the Ludlow series seen in the main Usk 
Inlier. 
In the i-inch map a third small Silurian inlier is shown 
near Lan-sor, half a mile to the South-East of Llandegveth, 
but there is now no exposure here. 
VI. THE FOLDING AND FAULTING. 
It has already been pointed out that there are two sets 
of disturbances to be seen in the Usk area. There is one 
which runs nearly N.N.E.-S.S.W., which has given rise to the 
two anticlines in the South, to the fault line which divides 
them, and to the fault which bounds the Silurian beds along 
their Eastern margin, and there is the other which has given 
rise to the East and West faults which cross the latter fault. 
W'hen considering the periods at which these two sets of 
disturbances took place, we must bear in mind the fact that 
in the Tortworth area the very thin development of Ludlow 
beds is thought to be due to upheaval and denudation during 
Old Red Sandstone times, and we may well imagine that in 
Old Red Sandstone times a certain amount of uplift occurred 
in the Usk region. 
There is no typical Downtonian at Usk, and there is no 
fossil evidence to show whether the yellow, somewhat coarse. 
