566 MULL. GEOLOGY. 



appertains to that which is dispersed throughout the 

 secondary strata, not only in the islands formerly exa- 

 mined, but in the neighbouring continent of Morven. 



On reviewing the whole of the strata which have thus 

 been described, it is apparent that they all belong to the 

 same deposit; whatever anomalies they may display, either 

 in their relative dispositions or in their connexions with the 

 surrounding rocks. It is evident that the limestones on 

 the east side of the island are parts of the lias series, 

 which has been already pointed out as existing in a simi- 

 larly dispersed manner in some of the islands before 

 described. It is equally evident from the facts already 

 stated, that the southern limestone appertains to the same 

 beds ; and there is no reason to doubt that the sandstone 

 on the western shore belongs also to this series, although 

 here very incomplete, and widely separated by the inter- 

 vening trap from the southern and eastern portions. 



In this island, as in others of the same character, the 

 separation of these now divided portions appears to have 

 resulted from the interference of the trap rocks. But 

 it is unnecessary to dwell on matters discussed in so many 

 other places ; particularly as the examination of Sky has 

 already superseded all that could be offered on the subject, 

 and as I shall hereafter, in giving a general view of the 

 Trap islands, have occasion to examine the mutual con- 

 nexions of all these dispersed strata with each other and 

 with the adjoining mainland. 



It is now necessary to describe the trap rocks. These 

 occupy by far the largest, although, to the geologist, the 

 least interesting portion of the island. It would not be 

 possible to give a full description of all the varieties of 

 these rocks or of the circumstances attending them, with- 

 out repeating the observations made on Sky or on the 

 other islands where they exist. Nor can it be necessary, 

 as the chief interest of such details consist in their scien- 

 tific, not in their topographical importance. 



Throughout the whole northern division of the island 



