Mhieralogy of Sky^ 29 



Oransa, the point being much less accurately defined on the 

 eastern than on the western shore. The shores which it forms are 

 generally flat and shelving, but in some particular places, as at 

 Tormore, it rises into high cliffs. The whole tract is however but 

 little interesting, since the uniformity of this rock is only varied by the 

 occasional occurrence of veins of trap and of quartz. If I could de- 

 termine that the beds of mica slate had a regular position, I would 

 say that they were succeeded by quartz rock, and that this rock 

 terminated near Loch Elshort, being followed by a succession of 

 rocks to be described immediately ; but to determine such a 

 succession, a regular disposition is indispensible, since, without that, 

 the uppermost in place may not always be the uppermost in order. 

 I must therefore content myself with remarking that the quartz rock 

 follows the mica slate in geographical position, and that its main 

 body will be seen occupying two hills which lie above Ord, from 

 which the skirts reach to the shores of the southern boundary of 

 Loch Eishort. The mica slate has no peculiarity of structure ar of 

 aspect, such as to render a detailed description of it necessary, but I 

 think it proper to remark, that like many other districts of the wes- 

 tern isles which contain this rock as the basis of their structure, it 

 is by no means so unmixed as it is generally met with in the exten- 

 sive tracts of it which occur on the main land. On the contrarv, it 

 is frequently found passing into clay slate as well as into talc and 

 chlorite slates, affording an example like Arran, Isla, and Jura, of 

 the intimate geological union which subsists between these several 

 substances. Of the quartz rock I may remark, that It is extremely 

 compact, of a higljly crystalline aspect in general, and that its wea- 

 thered surface is so v/hite as to render the hills which are formed of 

 it distinguishable at a great distance by their snowy appearance, 

 while at the same time.it is frequently varnished, as it were, ulih the 



