SKY. GEOLOGY. SECONDARY STRATA. 317 



may now be said to cease through all the remaining part 

 of the island. Although the whole of the scattered parts 

 in question must be referred to the same variety, perhaps 

 to the same deposit, of calcareous rock, yet the principal 

 interest is contained in the first and most extensive tract 

 that occurs, and from this alone the condition and con- 

 nexions of the more remote and detached portions are 

 capable of being understood. 



This division occupies the district and parish of Strath, 

 extending between the north-eastern and south-western 

 shores. On the south-eastern side it is chiefly bounded by 

 the sandstone already described ; while the opposite one, 

 stretching towards the syenite mountains, is extremely 

 irregular, being not only marked by indentations and 

 deficiencies, but confused in a manner that can not be 

 rendered intelligible either by words or drawings. Ge- 

 neral description must here supersede the use of particular 

 details, but it will be found adequate to the purpose 

 in view. I may add that the term limestone is used in 

 the following description as a general one, including 

 the alternating beds of shale and sandstone, which 

 will nevertheless be specially described wherever it is 

 necessary. 



Commencing from the lowermost beds it must be 

 remarked, that it is impossible to trace their common 

 boundary with the red sandstone, although there can be 

 no doubt that they meet in a line which may be drawn 

 from near Swishnish point to the farm of Lucy near 

 Broadford. This arises, partly from the irregular form 

 of the ground and the depth of boggy soil with which it 

 is covered, and partly from the intrusion of the syenitic 

 hill Ben na Charn, which is so placed as to cover a large 

 portion of the joint boundary of both rocks. It is probable 

 indeed that there is some disturbance of the limestone 

 even at its lowest boundary ; but as this cannot be dis- 

 covered, and as there is a general appearance of regularity 



