THE CLYDE ISLANDS. 499 



the sandstone appears, are not limited solely to those 

 parts which may be supposed to be covered by the sea, 

 or to have been removed by its action ; as similar appear- 

 ances may be traced on the mainland. It is an inter- 

 esting part of the history of that rock, and merits notice 

 in itself, independently of the elucidation which it offers 

 respecting the present state of these islands. 



There can be no reason to doubt the identity of the 

 whole deposit of red sandstone, from the east coast of 

 Scotland even to the western side of Canty re ; as it 

 possesses every where a set of common features, together 

 with a common relation to the strata which it follows 

 and to those which succeed it. But, throughout the 

 whole of this tract, it presents a great variety both of 

 dip and of direction ; the angles of elevation varying in 

 quantity, from the horizontal to a very high position, 

 and respecting different points of the compass. Where 

 the large tracts are examined, this variety of position 

 is found to result from the general undulating manner 

 in w r hich it is disposed ; depending apparently, in most 

 cases, on the irregularity of the base on which it has 

 been deposited ; while in others, it seems to be the 

 result of posterior changes which have at the same time 

 affected the primary rocks beneath. Although the want of 

 continuity prevents that undulating disposition from being 

 traced to any great extent among the islands, there is reason 

 to suppose that it has also existed, or that it even exists at 

 present : but at so low a level as to permit the sea to 

 flow over the strata. Thus their insulated state may to 

 a certain degree be accounted for ; although, in examining 

 the present condition of these rocks in many places, it will 

 be evident that a considerable loss of substance must also 

 have taken place before the islands received their present 

 forms. In comparing the actual inclinations of the se- 

 condary strata in the several islands, the existence of 

 such an undulation is evident ; and it is here unnecessary 

 to recapitulate the particular instances in which it has 

 been demonstrated. The effects of such a condition of 



