ACCOUNT Of PAPA STOUR. 163 



caves, which form commodious retreats for seals ; 

 and at different parts of the coast, there are naked 

 insulated projecting masses of rock, on which 

 myriads of sea-fowl hatch their young in safety, 

 the steep sides of these islets preventing even the 

 enterprising natives from reaching their summits. 



As the rocks of Papa Stour are of very different 

 degrees of induration, so the sea has in many 

 places made great encroachments, and formed 

 creeks and caves of considerable magnitude. These 

 present great obstacles to the examination of the 

 mineralogy of this island, in consequence of the 

 place of junction of the different rocks, being of- 

 ten covered by loose blocks of stone, or concealed 

 in the recess of a deep and gloomy cave. 



The strata are in general nearly horizontal, 

 seldom vertical, and in a few instances trough- 

 shaped and bason-shaped. In many places they 

 present appearances of much confusion. Immense 

 slips or translations of the strata have taken 

 place, whereby they have been depressed many 

 fathoms since their original deposition. These 

 translations are not confined to particular beds 

 of rock, but have taken place generally over 

 the island. In these translations, the beds on the 

 hanging side are always depressed, and lower than 

 the same bed on the lying side. Appearances of 

 this kind may be seen at Ungly-braed- head, and 

 Lammer-banks. 



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