44 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DeC. 5. 



small sizes, through a gradation, to that of large angular blocks. The 

 far-carried detritus comprises green slates, porphyry, and basalt, 

 which occur in the form of pebbles, boulders, and some large blocks. 

 The fragments of granite are only small and often angular. Among 

 these various stones may be found the representatives of most of the 

 rocks of the Lake- district. 



South of Horseleyhope Mill and Cold Eowley, the Drift occupies 

 the flank and summit of the hill, and from the latter place it spreads 

 down to the Derwent. On this declivity it is of a sandy character. 

 From Consett eastward it prevails rather partially on the higher 

 grounds until we come to ^\Tiickham, where it would seem to be more 

 regular. Boulders of Shap Fell granite lie on the bank below Whick- 

 ham. Carrock Fell granite also occurs in the valley of the Derwent, 

 with others which are evidently from Scottish localities. From the 

 third point dovm the hill-side to Witton-le-Wear, there is apparently 

 an absence of Drift. This may probably be the case on the slope to 

 the Wear eastward. On the north side of the hill, from its summit 

 to Dean House, it occurs in not a very marked character. Such it 

 may likely continue to be on the declivity towards the river Browney. 

 It is slightly traceable from the ridge south of Consett to near Lan- 

 chester. Thence to Durham it is apparently not traceable. At this 

 place much sand occurs. Among this there seems to be no granite 

 or other stones to mark it as the true drift. These sandy accumu- 

 lations at Durham, and those previously noticed, have evidently 

 resulted from the denudation of the Millstone-grit. 



From Witton-le-Wear bridge, following the road by West Auck- 

 land to near Staindrop, no indications of the Drift are met with. At 

 and near this place a few stray boulders of Shap Fell granite occur. 

 There are others in the neighbourhood of Barnard Castle. Thus 

 from a little north of Staindrop to Barnard Castle may probably 

 be near the range of the Drift- elevation on the north side of the 

 Tees. But on the south side of the river, Shap Fell granite occurs at 

 Lartington, and is likely to be found strewn down from here to 

 Barnard Castle. Thence down the north side of the river to Dar- 

 lington the miscellaneous character of the Drift prevails. Boulders 

 of Shap Fell granite are observable near Winston. In the North 

 Street at Darlington lies the well-known granite Shap Fell boulder. 

 Others of the same kind occur at Cockerton. On the road between 

 Cockerton and West Auckland there seems to be an absence of the 

 true Drift. Granite from Shap Fell and green slate and porphyry 

 from the Lake-district make up a part of the drift-materials on the 

 Tees. From what has been previously stated respecting the Drift on 

 the Stainmore ridge and on the eastern slope to Lartington, it will 

 now appear obvious that it has been carried over the ridge and down 

 to the mouth of the Tees. At one time it may have lain on the 

 Stainmore ridge in considerable quantity. From the Tees the erratic 

 blocks of Shap Fell granite have found their way along the eastern 

 declivity of the Pennine chain as far as the mouth of the Humber. 



