BIRDS OF SOUTH-EAST NORTHUMBERLAND. 379 



1910, I observed one of the white-breasted variety of the Cor- 

 morant off St. Mary's Island. I was shooting from a coble, and 

 the bird rose up from the water facing the wind, and with its 

 breast to me, the whole of which, together with the belly, 

 appeared dull white. This form is described in the * Field ' for 

 Nov. 6th, 1909, and also in ' British Birds.' The bird I saw had 

 not any white on the throat or neck. William Turner, in his 

 Commentary on the Birds of Pliny and Aristole (1544), says : 

 *'....! have seen Mergi [Cormorants] nesting on sea cliffs 

 about the mouth of the Tyne river. . . ." Some of the cliffs 

 here referred to are doubtless those of Tynemouth. While 

 touching on the subject it would perhaps not be inappropriate 

 to give a short sketch of the geological features of the district. 

 These have for many years been a source of trouble to geolo- 

 gists. The strata of the rocks along the coast have been so 

 broken up that in some cases it is difficult to define them. This 

 peculiar action is believed to be due to a great thrust from the 

 north, which has probably originated in the elevation of the 

 Cheviot range in a former geological age. The coast-line is 

 composed for the most part of coal-measure rocks, but there 

 are blocks of magnesium limestone (Permian) let into the cliffs 

 by faults at three points, viz. Tynemouth (Cullercoats), Whitley, 

 and Seaton Sluice. The outcrop of this limestone at Tyne- 

 mouth is very large, and forms the whole of the cliff on which 

 the castle stands ; that at Whitley and Cullercoats is also of 

 considerable size. A large quantity of limestone occurs at 

 Whitley Dene, and it was formerly quarried, thereby forming the 

 depression for the reservoir. The lime was extracted in kilns, 

 which still remain, and form ample nesting-sites for Sparrows 

 and Starlings. Marl slate is in evidence at Cullercoats, forming 

 the base of the magnesium limestone, and seams of pulverized 

 coal occur along the face of the cliffs on the south of George's 

 Point, and also on the cliffs near St. Mary's Island. This latter 

 is sometimes broken off and strewn in large quantities on the 

 foreshore by the waves. There is an outcrop of yellow sand- 

 stone at the extremity of George's Point, Cullercoats, and again 

 at the base of Cullercoats Bay, several large caves having been 

 bored in it by the action of the tide. These sandstone cliffs 

 have been proved by the nature of the particles of sand to be of 



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