152 Professor Sepawick on the 
on the S.W. side of the valley, opposite Middleton, is crowned 
by the four fathom limestone (No. 26.) and a thin bed of grit. 
If, therefore, we assume that the great bed of trap is the repre- 
sentative of the Whin-Sill (No. 71.) ; it follows that the beds we 
pass over in ascending to the top of the mountain, must tally 
with those of the general section between No. 26. and No. 71. 
I confess that I have considerable doubts of the entire accuracy 
of this statement, as it assumes a consistency in the relative situa- 
tion of the bed of trap, which we do not find in other localities. 
There can, however, be no doubt that many strata on the south 
side of the valley, are higher, perhaps by three or four hundred 
feet, than the corresponding strata on the north side*. 
oe of the This derangement in the neighbouring parts of the same 
formation, can only be accounted for by the prolongation of the 
great Teesdale fault in a direction nearly parallel to the escarp- 
ment of the trap. The attention of several practical men has 
been directed to this phenomenon, under the expectation of finding 
metalliferous deposits along the line of dislocation. Though dis- 
appointed in this expectation, they have found direct evidence for 
the existence of the fault in several places where the strata are 
laid bare by the river. I shall proceed to point out a few of the 
localities. 
The indications of the great longitudinal fault in the bed of 
the river above Eglestone Bridge and on the right bank of the 
Lune, have already been pointed out. Similar appearances are 
seen farther up the valley on the road leading from Middleton 
to Lonton. The line of fault, though unquestionably continued 
on the south side of the river, is for some way lost in diluvium ; 
but it is afterwards distinctly exposed in two places on the side 
* See the section of Teesdale, Pl. virt. Fig. 1. The dislocation in this part of the valley is 
many times greater than that which is exhibited below the junction of the Lune with the Tees. 
