454 BUTE. GEOLOGY. 



when the description of these rocks is given, that the 

 obscurity and confusion here existing is, as in many 

 other cases, of an artificial nature, and the result of a pre- 

 conceived regularity that has no existence in nature. 



From these circumstances it becomes necessary to give 

 a general sketch of the nature of the schistose rocks of 

 Bute and Arran, as they occur on that prolonged line 

 which stretches through the mainland ; which was already 

 mentioned, in treating of the latter island, as being con- 

 tinuous in geological structure with the analogous portions 

 of both. The structure of Bute will thus become imme- 

 diately intelligible ; while the general interest of the facts 

 will be increased ; although at the risk of transgressing 

 on the province of those who may hereafter undertake 

 the description of the continental rocks. 



In the account of the chlorite series of Argyllshire, 

 it was shown that a tract of micaceous schist succeeded it 

 towards the south, being continued in that direction as 

 far as the Mull of Can tyre. At that place, it is imme- 

 diately followed by the red sandstone, without any inter- 

 posed substance; a fact easily explained by considering 

 the unconformable relation of this rock to the primary 

 strata, and the irregularity of its margin consequent 

 on the peculiar situation which it occupies with respect 

 to these. The same schist may be traced from this pe- 

 ninsula, as far at least as to the mountains of Mar; 

 beyond which it is not necessary for the present purpose 

 to examine into the structure of the mainland. The di- 

 rection of the beds throughout the tract which it occu- 

 pies, is in a general sense north-easterly, and parallel 

 to the southern limit of the series ; subject to the usual 

 irregularities which have so often been mentioned. A 

 great variety of dip will be seen to exist through this tract, 

 if the whole space be examined; but on the southern 

 margin, or boundary of the series, the inclination will 

 generally be found toward the south-east. That boundary 

 may be traced, in the direction already mentioned, from 



