SKY. GENERAL DESCRIPTION'. 23 



of some prominent and unsettled points in geological 

 science. 



The extreme length of the island appears to be about 

 forty-five miles, and that line, lying between Vaternish 

 point and the point of Sleat, is not materially different 

 from a mean length of its sides, considering it as a 

 parallelogram. Its extreme breadth lies between Cop-* 

 nahow point and Ru na braddan, and may be taken at 

 twenty-four miles ; but a more correct general idea of its 

 superficial dimensions will be formed by measuring nearly 

 across the middle of the island, which will give a mean 

 breadth of fifteen. The superficial content does not how- 

 ever correspond to these measurements, in consequence 

 of the remarkable indentations of the coast; the sea 

 entering on all sides in such a manner, that it is 

 difficult to find a place five miles distant from the shore. 

 Its boundary is almost every where rocky and elevated ; 

 often rising into cliffs of great altitude, no less remark- 

 able for their picturesque forms than valuable to the 

 geologist for the display which they afford of the interior 

 structure of the island. 



The surface of Sky is almost invariably hilly, pre^ 

 senting three distinct assemblages of mountains separated 

 by intervening tracts of high and undulating land : the 

 plain of Kilmuir and a small tract near Loch Bracadale 

 are the only exceptions. As these differences of exterior 

 character are generally accompanied by changes of the 

 component rocks, I shall, in describing the several 

 divisions, slightly notice the prevailing substances, pre- 

 paratory to the more minute details into which it will 

 afterwards be necessary to enter. 



Commencing with the southern division, a continuous 

 ridge is found extending from the point of Sleat to Loch 

 in Daal, where it suddenly subsides into a low tract 

 stretching northwards towards Broadford. The general 

 elevation of this ridge may be estimated at twelve hundred 

 feet, or more ; and it nwv be considered as continuous 



