340 C. E. Be Ranee — On the Surface- Geology of Cross Fell. 



tremely sliallow valley, with, a peat-covered alluvial plain, bounded 

 by low cliffs, which, increase in height to some sixty feet at Provi- 

 dence Vein, opposite the sources of the Tyne. The slope of the 

 covintry is that of the beds ; but the latter dip at a rather stronger 

 angle, the lowest of the Cross Fell beds being, however, the Great 

 Whin Sill. 



The whole of this Upper Tees Valley would appear to be pre- 

 glacial, for Boulder-clay occurs on the cliff tops well within the 

 very head of the valley under the col. The gradual denudation of 

 valleys by river-action is well seen in the higher course of the 

 South Tyne, and of the Tees. Between Alston and Garrigill, 

 strong stone walls, locally called Warrens, built in the last century 

 to keep the river from eating away the land, are now in the centre 

 of alluvial meadows, some distance from the river, and several feet 

 above its level. In some places there are at least three terraces, 

 but generally they have been swept away by the river, which 

 constructs a fourth with a portion of their debris, and new spoils 

 from above. From Garrigill, which is built on the lowest alluvial 

 terrace, to Tynehead -Smelt Mill, the river flows on the Tyne- 

 bottom Limestone ; a little north of this point the " Great Sulphur 

 Vein" brings the Great Whin Sill to the surface, which forms a great 

 boss, more or less glaciated, and covered on the west side of the 

 river with dark-grey Boulder-clay, with many rounded and sub- 

 angular stones, most of which are scratched, at an elevation of 

 1560 feet above the sea. The river has cut a narrow notch through 

 the basalt, but not completely, for there is a small waterfall — ■ 

 " Tynehead Force." In the deep tributary valley of Shield Waters 

 there is a much finer waterfall, Cashburn Force, also on the basalt ; 

 fine cliffs of columnar basalt were also found by Prof. Hull and 

 myself near Smittergill Mine. 



Above the Smelt Mill the deep glen gradually contracts the cliffs 

 on either side, until, at the source of the Tyne, two long sweeping 

 peat-covered slopes range upwards to the top of Bel Beaver Eigg 

 to the east, and Noonstones to the west ; the top of the former hill 

 is said once to have been a Eoman camp. 



From the top of the col, above the source of the Tyne, the ground 

 on the other side slopes gradually down to the nearest point of the 

 Eiver Tees, which flows past in direction nearly at right angles to 

 the course of the Tyne. Thick deposits of dark grey Boulder-clay 

 form the banks of Crookburn, above the Tyne-bottom Limestone, 

 which is glaciated near its junction with the Tees. I found 

 Boulder-clay as high as 1770 feet towards the source of the river, 

 but none on the col between Tees and Tyne, or the still higher col 

 between the Tees and Crowdundle beck, which runs into the 

 Eamont, in the vale of Eden, resting on the Permian sandstone of 

 that vale. Between Penrith and the foot of Cross Fell are sheets of 

 Upper Boulder-clay, with an underlying sandy gravel, which in 

 Melmerby, Ousb}'', Blencarn, and Skirwith, contains erratic rounded 

 pebbles of the Lake-district, much resembling in character, as well 

 as in that of the matrix, the Boulder-clay of Lancashire. Erratic 



