GEOLOGY. ly 



In the dale of the Greta we have only the upper half of the 

 series visible. The Middle Limestone may be seen in the deeply 

 excavated river bed near Rutherford Bridge, and the Flagstones 

 above it are quarried extensively about Brignall and Scargill. 

 The junction of the Tees and Greta is in the Main Limestone 

 at an elevation of 380 feet, and the same rock, with its beds 

 dipping steeply towards the north, forms the bed of the Tees * 

 beneath the well-known Abbey Bridge of Egglestone, and the 

 equally well-known scars that margin the Greta in Rokeby 

 Park. From this point the Main Limestone may be traced 

 along the edge of the fells which border the dale of the Greta 

 to an elevation of nearly 1,000 feet at Bowes, and from thence 

 along the south side of the dale by way of Gilmonscar, past the 

 summit of drainage between Arkengarthdale and Swaledale to 

 Gilling, and from thence back again to Rokeby, beneath 

 Gatherley Moor by way of Forcett and Hutton Magna : and a 

 small isolated tract of limestone is also to be seen on the east 

 of the gritstone at Middleton Tyas. 



Between Gretadale and Lunedale there is a synclinal fold 

 or trough in the Mountain Limestone, dipping from the south 

 and north towards Deepdale and Balderdale, so deeply that in 

 this tract of country the Yoredale Rocks are altogether buried 

 beneath superincumbent masses of Millstone Grit. Along the 

 line of Lunedale a fault runs which elevates the strata on the 

 north of it to the extent of about 1,000 feet. Another fault 

 passes from the Caldron Snout along the line of Maize Beck 

 between Mickle Fell and Birkdale, elevating the strata on the 

 south-east, and a third along the line of the main dale of the 

 Tees, throwing up the beds towards the south, which in the 



* ' That mighty trench of living stone, 



Where Tees, full many a fathom low. 

 Wears with his rage no common foe, 

 Nor pebbly bank, nor sandbed here, 

 Nor clay-mound checks his fierce career, 

 Condemn'd to mine a channel'd way 

 O'er solid sheets of marble grey.' 



Scott's Rokeby. 



Bot. Trans. Y.N.U., Vol. 3. 



