Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/67



The metalliferous or lead-mine measures form the northern and western boundaries of the Coal-field. This formation enters Northumberland from the northern side of the Tweed, and constitutes its southern banks from its junction with the Tiviot at Kelso to the sea. In a south-eastern direction it follows the coast from Berwick to the Coquet for 32 miles. The porphyritic mountains of Cheviot interrupt it towards the west for about 20 miles; but having passed the southernmost point of that ridge it stretches across the whole breadth of Northumberland, and is spread over the adjacent borders of Cumberland, Durham, Westmoreland and Yorkshire. It is terminated towards the west by the red sandstone near Brampton and Melmerby, about 54 miles from the sea at Tynemouth and at Seaham.

The characteristic features of the north-eastern part of this district are gently swelling hills, heightened occasionally by mountain caps of basalt, and then assuming a rugged and broken aspect on their summits. Towards the western part of Northumberland it forms sterile moor-lands and exposed sheep-pastures, being still accompanied by basaltic eminences: the river vallies, however, that intersect these wastes, are fertile and picturesque in a high degree. If a line be drawn across the island through Newcastle and Carlisle, the highest station between the German ocean and the Irish channel is not more than 445 feet above the level of the sea; upon this spot the village of Glenwhelt is built. On the banks of the South Tyne