Northumberland and Durham. 75 



interstices of the basalt I have noticed ironclay of a brick-red colour, 

 and at Glenwhelt Mr. Fryer detected small veins of dark leek-green 

 talc in thin leaves mixed with iron pyrites and calcareous spar. 

 This fossil on being exposed to the action of the blow-pipe divided 

 into extremely thin folia, and changed from green to copper colour : 

 with the addition of borax it melted into a greenish black bead. 



These overlying masses of basalt appear also at Barwesford on the 

 North Tyne, and are continued to the vicinity of Thockrington and 

 Bavington, to Kirk Welphington, and thence in a north-easterly di- 

 rection as far as Causway-park, north of Morpeth. 



Proceeding further to the north, basaltic eminences form a striking 

 feature in the country between Alnwick and Berwick. These emi- 

 nences have frequently been chosen for the sites of castles, as at 

 Dunstanborough, Bamborough, and Holy Island. The hills near 

 Belford, the rocks called the Staples which emerge from the sea at 

 the distance of six miles east of Bamborough, and the Fern Islands 

 situated half way between the Staples and the shore, are likewise 

 composed of basalt. • 



At Craster near Howick, where the millstone grit is also found, 

 basalt was formerly quarried and shipped to London for paving- 

 stones. Craster house is fronted with this rock. 



In the north-eastern face of the cliff, on which the ancient fortress 

 of Dunstanborough stands, the following series of strata is exposed 

 to view : 



Columnar basalt - - from 8 to 10 feet 



Sandstone ----.--2 



Shale - - 6 . 



Basalt 



K 2 



