Page:Medieval Military Architecture in England (volume 1).djvu/507

 MedicBval Military Architecture. 4C1 CORFE CASTLE, DORSET. CORFE Castle is one of the most noteworthy remains in Britain. The natural position is very striking, and not less so the manner in which it has been fortified by art. It is of high antiquity, associated from the times of the West Saxon princes to those of the Commonwealth with marked historical events ; was the palace and the prison of kings and great nobles, and has been commanded by a long succession of powerful Castellans. The castle crowns an isolated hill, a part of the steep chalk ridge which, under the general name of the Purbeck Hills, with the sub- ordinate elevations of Knowl Hill, and Ninebarrow and Ballard Downs, stretches twelve miles across the peninsula of Purbeck, from Warbarrow Bay and Flovverbarrow Camp on the west, to the foreland between the bays of Studland and Swanage on the east. To the south, or seaward, is the bold coast line marked by the headlands of Peverel, Durlston, and St. Adhelm's. Landward, or to the north, is the depression occupied by Poole Harbour and its tributaries the Frome and Trent, or Piddle — waters whose fords are commanded by the grand earthworks at Wareham, which, placed astride upon the ridge terminating in the junction of the two, form the frontier and key of Purbeck, as does Corfe, its citadel. The castle ridge ranges with the Isle of Wight, and with it forms the southern margin of the well-known chalk basin, of which Dor- chester and Beaminster mark the western limit, and Beer Regis, Salisbury, and Winchester that on the north. The chalk at Corfe dips north at about 70°. It is hard, mode- rately durable, and thickly charged with flints, which are extensively used in the interior of the castle walls. Below the chalk, and under- lying the great gateway of the castle, is a narrow belt of the upper greensand, below which, in succession, are the three Purbeck beds, the Portland stone, and the Kimmeridge clay. The stone beds, here of a most durable character, are used for the ashlar and face- work of the castle. To the north of and above the chalk are narrow and irregular beds of plastic and London clay, succeeded by a broad expanse of the lower Bagshot sands and clay, out of which the harbour of Poole has been eroded, and the latter of which is worked for the purpose of commerce. A considerable fault runs along the chalk ridge close north of the castle hill, one of a parallel series traversing that part of the southern coast. The physical aspect of Purbeck betrays, to a practised eye, its geological composition, and the wild rough moor and marshland about the harbour contrast strongly with the steep but rounded outline