260 COLONSAY AND ORANSAY. GEOLOGY. 



fissures resulting from the dislocation of the schistose 

 rocks of which they are composed. Considerable banks 

 of shell sand are thrown up in various places along 

 the western sides of both islands : in Oransay this 

 substance forms a large portion of the surface. 



Some small remains of a monumental and religious 

 nature are to be seen in Colonsay ; but Oransay still 

 presents one of the most entire and extensive ruins 

 of the ancient monastic establishments of the Western 

 isles. As a very ample account of these relics has 

 been given by Pennant, it is unnecessary to take further 

 notice of them. 



The predominant rock of these islands is micaceous 

 schist, often approximating to chlorite schist and to 

 clay slate, and presenting a smooth and glossy surface. 

 It is generally attended with numerous and conspicuous 

 contortions. Some varieties of a quartzose micaceous 

 schist, and of quartz rock, also occur; but as there 

 is nothing to be found here which has not already been, 

 perhaps more than sufficiently described, I shall forbear 

 to enumerate these uninteresting particulars. It is only 

 necessary to remark, that at the farm of Ballyremondhu, in 

 Colonsay, a thin bed of limestone is found interposed in 

 the usual manner among the schist. The relation of 

 these islands to those which lie to the eastward, will 

 be readily deduced hereafter from the general remarks 

 on the structure of the Schistose isles that will conclude 

 the account of this division. 



