YORKSHIRE NATURALISTS IN UPPER TEESDALE. 289 



a mile further south. This is about 1,300 ft. above sea-level, at 

 the top of Kirk Arran, and he reported that the basalt was distinctly 

 nodular in character, and appeared to be a dyke about 60 ft. wide, 

 cutting its way through the limestone from west to east ; the stone 

 is darker and denser than that of Middleton, and is said to be very 

 durable. 



The remainder of the party proceeded along the road at the 

 base of the great basaltic scars, which form such a striking feature 

 in the landscape on the south side of the Tees, backed again as they 

 are by still loftier heights of limestone. The cause which thus 

 materially alters the scenery of this part of the dale is the great 

 Teesdale fault which throws up the Whin Sill on the Yorkshire side 

 of the river, whilst on the Durham side it is below the surface. 

 Thus, as the leader said, the strata on the north side are in their 

 regular order, but on the south side they are upheaved by the fault 

 some 500 ft. Some very complicated problems and phenomena 

 arise from the manner in which this district has been rent and 

 dislocated by igneous dykes and immense faults. In an old working 

 near the road-side we were shown where iron-ore had been worked, 

 but not in profitable quantities ; here was strong evidence of the 

 fault, as the face of the limestone could be seen. At Park End 

 Wood — a relic of the old Teesdale Forest — the party divided, and 

 most of the members visited Fairy Dell, and thence climbed to the 

 top of the scars for the view to be there obtained. Holwick Scars 

 were next passed, where the basalt rises in tremendous precipices, 

 whose vertical sides show remarkably well the columnar structure. 

 From thence the fields were crossed to view the Winch Bridge — 

 a seemingly frail structure composed of a few planks of wood hung 

 across the river, whose waters were turbulent enough just below to 

 make the position to feel at least novel. Here the Whin Sill appears 

 in the bed of the river, causing many miniature cascades. The 

 appearance of the basalt there on the north side of the fault shows 

 that the dislocation between this point and Holwick Scars is not so 

 great as was noted earlier on in the day. The party now proceeded 

 further to Holwick Head Bridge (near which the great fault crosses 

 the river), over which they crossed and pursued the road to the High 

 Force Inn, where a hurried tea was despatched, and a still more 

 hurried meeting held. This was absolutely necessary to enable the 

 bulk of the party to reach their distant homes the same evening. 



Thus terminated a most pleasurable and profitable excursion in 

 one of the grandest and wildest parts of Yorkshire. Many old 

 friends had once more met again to interchange views and opinions, 

 and much too had been seen to think over after returning ; the 



Oct. 1889. T 



