HUGHES : INGLKBOROUGH. 
339 
junction between them and the more tough and unyielding Silurian. 
The depression in the pre-Carboniferous surface was filled with lime- 
stone and conglomerate, and, moreover, as usual in the case of the 
deeper hollows, caused the conglomerate to be made up almost 
entirely of fragments of the underlying rocks, so that it is easily 
confounded with the thin line of basement bed of the Silurian which 
is also composed of fragments of the Bala series. As the subter- 
ranean denudation of the Mountain Limestone went on this depression 
determined that the spring should come out here, and resulted also in 
this deeper portion of the basement bed of the Carboniferous being 
prolonged further out into the valley. A little care, however, and, 
after floods, a little clearing of the torrent debris, enables us to dis- 
tinguish and work out the relations between the two basement beds. 
In Ribblesdale, the next valley on the east, the Coniston Lime- 
stone series is exposed at Crag Hill and west of the village of Horton. 
The section at Crag Hill is full of interest for the stratigraphist and 
palaeontologist, and would well repay careful detailed work. The beds 
are brought to the surface by a sharp anticlinal fold, the axis of which 
runs about 10° S. of E. 
The fall of the ground to the east is greater than the inclination of 
the anticlinal axis in the same direction, and therefore we find higher 
and higher beds of Bala series as we ascend the hill, and at last see the 
Silurian beds folding over the Bala series 100 feet or so below the base 
of the Mountain Limestone, as shown in the diagrams (Figs. 15, 16, 
17) in which are given a ground plan (Fig. 15), a section along the 
axis (Fig. IG), and another at right angles to it (Fig. 17). 
Behind and above the farm there is a fine section exposing a large 
cliff of limestone and calcareous shale split off so as to expose the 
upper face of the rock. On this numerous well-preserved specimens 
of characteristic Bala fossils were to be seen weathered out. Most of 
the more obvious of these have been long ago collected, but plenty 
may still be found with a little care and trouble. The following is 
a list of those determined : — 
Heliolites interstinctus Wahl. 
Stenopora (Favosites) fibrosa Goldf. 
Petraia {Streptelasma) cequisulcata M'Coy. 
B 
