Dislocation 
below Winch 
Bridge. 
Strata. inferior 
to the Trap. 
Forcegarth 
Hill. 
158 Professor Sepawick on the 
The chasm through which the Tees descends may have been 
considerably modified by the long continued action of the waters, 
but its general form must have originated in some more powerful 
cause. A little way below the bridge there are indications of a 
considerable dislocation, by which the inferior beds have been 
brought out, from beneath the trap, into the right bank of the 
river. The appearance of the rocks in that locality is represented 
Pl. 1x. Fig. 2. 
I think it unnecessary to describe the phenomena exhibited 
in the bed of the river between Winch Bridge and Holwick 
Head, because they throw no light upon the relation of the 
trap to the inferior and superior strata. At Holwick Head the 
line of fault (as was stated above, p. 153.) crosses the bed of 
the Tees, and a few hundred feet above that place the inferior 
strata begin to rise from beneath the Whin-Sill, and gradually 
occupy the lower part of the lofty escarpments which extend on 
both sides of the river to the High Force. They are composed of 
limestone, slate-clay, and sandstone, and are exactly parallel to the 
lower surface of the super-incumbent whin-stone. The relations 
of the several beds to each other, are finely exhibited in different 
natural sections, but more especially at the High Force, where 
the whole system of strata forms one grand escarpment, over 
which the waters descend by a single plunge of sixty feet. Of 
the picturesque features of a place which has been so long and 
so justly celebrated, it is not my intention now to speak; but 
I may observe, that the interest of the scene is greatly height- 
ened by the singular contrast presented by the horizontal beds 
which form the base, and the prismatic masses of trap which 
form the crown of the escarpment. 
For two or three hundred yards above the great water-fall, 
the trap again occupies the bed of the river. It is then thrown 
out into the side of Forcegarth-hill, partly by the natural rise of 
