510 EGG. GEOLOGY. 



side, the whole shore is rocky ; affording no other harbour 

 than that which is formed by the small detached island 

 Eilan chastel, fit only for ships of small burthen. The 

 general surface is uneven and undulating, being diver- 

 sified with small hills and terraces ; while towards the 

 southern side it rises to its highest elevation at the Scuir, 

 and on the northern to a height somewhat inferior. There 

 is some green and arable land at the bay of Lagg, and a 

 considerable proportion of the same soil at the eastern 

 side, where the island gradually subsides to the sea ; while, 

 with a few exceptions of no importance, the rest of the 

 surface consists of a heathy or mossy pasture, applied 

 to the rearing of black cattle, which here constitutes the 

 chief object of rural economy. The height of the Scuir 

 from the level of the sea appeared from barometrical 

 observation to be 1339 feet. Though the opposite eleva- 

 tion is considerably lower, I had no opportunity either of 

 measuring it or of forming an accurate estimate of its 

 relative height. This island has neither extent or eleva- 

 tion to admit of the accumulation of any considerable 

 stream, possessing two or three brooks only, scarcely 

 worthy of notice. Nor does it present any traces of allu- 

 vial or of transported matter, excepting that which forms 

 the great slopes at the feet of the basaltic cliffs, and at 

 the base of the Scuir ; being produced by the annual waste 

 and ruin of those rocks. 



As the position occupied by the trap rocks prevents the 

 secondary strata from being sufficiently detailed in the 

 map, I have added such a general section of the island 

 as will assist in rendering its description more intelligible.* 



IN a general view, the island of Egg consists of a large 

 body of trap, which, as the section shows, may be con- 

 sidered as forming a great bed, dipping towards the 



* Plate XIX. fig. 1. 



