Mr. Hut ton on the Stratiform Basalt. 189 



On the side of the hill south of Aglionby Burn, the Whin was a short 

 time ago worked into in a mine called Foxfold Level. 



In the higher part of Smitter Gill, the Whin may be seen forming the 

 west cheek of a vein ; it occurs again by the throw of another vein near 

 the foot of this stream, a little above its junction with Shield Water, 

 where it may be seen in the bed of the burn for above 100 yards. In 

 Routen Burn, Swarth Beck, and Kesh Burn, the waters form beautiful 

 cascades over the Whin, which appears in each of these situations, from 

 the crossing of a vein, called by the miners the Great Vein, or the Back- 

 bone of the Earth.* At Kesh Burn it is not less than SO fathoms thick. 



The Tyne itself is precipitated over the Whin by the influence of the 

 same vein near Tyne Head Smelt Mill, where the water forms a suc- 

 cession of falls, which, together, are not less than sixty or seventy feet 

 in height.t This is the only spot on the river Tyne, where the Whin 

 Sill is visible, it was however sunk into at Beldy Mill, on the south bank 

 of the river near Garrigill Gate, and found to be 20 fathoms thick. 



In the river Wear the Whin is visible at Unthank Bridge, near Stan- 

 hope ; it may also be seen at Rookhope Burn, where it has been de- 

 scribed by W. C. Trevelyan, Esq.t 



In Kilhope Burn, which afterwards becomes the Wear by its junction 

 with Burnhope Burn, at Wear Head, the Whin Sill may be seen at 

 Burtreeford, where it appears to be broken by the action of a great 

 Basaltic Dyke, the peculiarity of which will be afterwards referred 

 to. 



In Teesdale, from below Middleton, the Whin Sill is the predomina- 



* The Great Vein which well deserves its name, from the extent of its throw and its 

 magnitude, is filled with Quartz, massive and crystalline, having long-bladed crystals of 

 Iron Pyrites embedded in it. It apparently obtains the name of the Back-bone, from a 

 ridge of Quartz, which, standing above the surface, marks the line of its course. 



f Above the higher fall at Tyne Head, a Basaltic Dyke is seen cutting the strata perpen- 

 dicularly, and forming a ridge on either side of the river; direction N. N. W. In the bed 

 of the stream, when the water is low, it may be seen intersecting a Limestone without alter- 

 ing its level. This Limestone is above the Whin Sill, and appears to be little altered either 

 by its proximity to that bed, or the Dyke ; the Shale bed above it, however, which the 

 Dyke also cuts, is considerably hardened. 



X Vol. i. page 58. 



