Geology of High Teesdale. 151 
intersects the faulé above described not far from the junction 
of the two rivers. Some complex phenomena result from this 
double dislocation, especially at Leeky Hill (in the angle between 
the Lune and the Tees) where the great limestone (No. 21.) is 
brought in contact with the high brigstone hazle (No. 33.) 
Above the entrance of the Lune, the true order of the Yo! 
strata on the north side of Teesdale may be ascertained without the opposite ¥ 
much difficulty. The low brigstone hazle (No. 37.) occupies the can 
bed of the river near Middleton, and the great limestone is, there- 
fore, to be sought at a considerable elevation on the side of the 
neighbouring mountain. To pass the outcrop of the other beds 
(below No. 37.) we must ascend still higher up the valley, and 
we may then observe the whole series (to No. 71. inclusive) 
rising in regular succession from beneath the upper parts of the 
formation. 
Since the mean direction of all this part of Teesdale is nearly 
transverse to the general bearing of the strata; it is obvious that 
the same rocks might be expected to appear in both sides of 
the river. If, however, we cross to the right bank of the Tees, 
we find a bed of trap (to which there is no counterpart on the left 
bank) commencing near Lonton, and forming a very grand 
escarpment near the base of the mountain, until it stretches over 
the bed of the river about four miles aboye the place of its first 
appearance. 
The strata which form the support of the trap, before it 
extends over the bed of the river, are generally concealed by 
diluvial gravel and vegetable soil; but the strata which rest upon 
it may be conveniently examimed in many places on the flanks 
of the mountains which range on the south side of High 
Teesdale. Those who are best acquainted with the features of the 
country assert that they have in this way detected al! the prin- 
cipal beds of the general section, It appears that the mountain, 
