448 BUTE. GENERAL DESCRIPTION. 



schistose strata of which the whole is composed, are always 

 the same ; if we except the very few capricious variations 

 which are rarely altogether wanting in similar cases. This 

 direction is to the eastward of north, and the dip is to the 

 southward of east ; being commonly at a high angle, 

 but varying between twenty and sixty degrees. As the 

 bearing of the main ridge, and the parallel outlines of the 

 island, are north-westerly, the direction of the strata is 

 consequently neither parallel to these nor transverse, but 

 at an oblique angle : while, at the same time, it is occa- 

 sionally either parallel or transverse to the other eleva- 

 tions which are not coincident in direction with the prin- 

 cipal one. 



It is so seldom that we are enabled very unquestionably 

 to compare the directions of the strata of primary rocks 

 with those of the ridges and groups of hills which they 

 form, that it is proper to notice them whenever they 

 can be ascertained. Such remarks may be useful in pre- 

 venting us from concluding too hastily, that the forms of 

 mountains necessarily depend on the position of their 

 strata; since in this case it is apparent, that while the 

 direction and dip continue to be the same, and the nature 

 of the rocks identical, every possible form, and every 

 variety of position and outline, occur in the mountains that 

 are composed of them. 



The separation of the primary from the secondary dis- 

 trict, takes place, as before remarked, in a low and narrow 

 valley extending from Rothsay to Scalspie bay; and is 

 accurately defined by two small fresh water lakes which 

 occupy that valley, and by the streams that flow from 

 them on each side to the sea. The largest of these, Loch 

 Fad, is about a mile and a half in length, and the least, 

 Loch Stuck, about half a mile. The junction of the two 

 classes of rock at this place, is to be considered as a 

 continuation of that principal and extensive line on the 

 mainland, which may be traced from the eastern sea ; but 

 it varies here in some particulars from the general cha- 



