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THE SCOTTISH NATURALIST 



were some about half a mile to the east of the Head ; and 

 one pair certainly nested about three miles to the west, on 

 the Thurso side of the Head, in 1906. By that time there 

 were as nearly as could be made out fifteen pairs below the 

 lighthouse (nine pairs on the east side, and six pairs on 

 the west side), evidently nesting. On 1st June 1905 a pair 

 was seen hovering about Holborn Head, on the west side of 

 Thurso Bay (J. A. H.-B., Ann. Scot. Nat. Hist., 190;, p. 118). 1 



Holborn Head. 



The diagram in the text showing the dip of the Caithness 

 pavement to the west of Scrabster (Thurso) Bay — at Hol- 

 born Head and the Clett Rock — does not represent the 

 strata of the cliffs of Dunnet Head to the east of Scrabster 

 Bay, because at the latter higher cliffs there is a cap of much 

 more friable " Hoy " sandstone (Heddle), which, running in 

 horizontal ledges near the cliff- summit and disintegrating 

 there, affords ample foothold, nesthold, and a luxuriant 

 vegetable growth, affording excellent nesting-ground for the 

 Fulmars, as they also do — or did ? — for Cormorants. 



1 In the Annals for 1906, p. 204, it is stated that on 3rd June 1905 

 there were twenty-two pairs breeding at Dunnet. 



