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Dunstanburgh Castle. By George Tate, F.G.S., &c. 

 {Read at the meeting at Dunstanburgh Castle, August 26th, 1869). 



Dunstanburgh Castle, though having but a short history, 

 and being now but a ruin, has nevertheless many attractions 

 to the archaeologist ; and standing on pillared basaltic rocks, 

 rising one hundred feet above the shore, it forms a picturesque 

 scene, which has been idealised by the genius of Turner. 



This basalt is part of the Whin Sill, which, in its course 

 southward, curves inland from Newton Point, and sweeping 

 round by Embleton appears in great crags at Dunstanburgh, 

 with high cliffs on the north and west, and a rapid slope into 

 the sea on the east ; it extends southward along the shore 

 for two miles as far as Cullernose, where it bids adieu to the 

 coast, and passing by Howick Hall, Longhoughton, and 

 Ratcheugh, pursues a south-westward course through the 

 county of Northumberland. 



When of considerable thickness, this basalt has a rude 

 columnar structure, which is well shewn in the northern 

 cliff, in the detached pillars on the west side, and in the 

 gut of the Rumble-churn on the east, where the columns 

 are so distinct, as to resemble the more regular forms 

 at Staffa and the Giant's Causeway. Crystals of quartz, 

 some white and transparent and others of a violet hue, have 

 occasionally been found in cavities of the rock in the eastern 

 part ; and, as such minerals are not common in Northumber- 

 land, they are popularly celebrated as Dunstanburgh diamonds 

 and amethysts. 



The relation of the basalt to the stratified rocks is shewn 

 in the northern cliff, where the columnar basalt, which is 

 above forty feet in thickness, overlies beds of sandstone, shale, 

 and coal, belonging to the Mountain Limestone formation. 

 A little northward of the cliff on the sea shore there is a con- 

 torted limestone, which has a sharp anticlinal axis, and has 

 hence been called the Saddle-rock ; it dips away south-east- 

 ward towards the basaltic cliff", under which it passes ; and 

 it extends also to the sea bank, where it is covered by the 

 Boulder Clay, in which are large glaciated blocks, and where 

 its upper surface is polished, striated, and grooved, some of 

 the grooves being a quarter of an inch in breadth and running 

 in parallel lines in the direction of north-west to south-east. 



Both the chemical and mechanical action of the basalt on 

 adjacent rocks is seen here ; in the Rumble-churn the basalt 



