L. A. Necker tie Saussure Voyage en Ecosse. 185 



Considerably to the north of Brodich is a Loch Ranza. 

 Here a curious geological phenomenon occurs. The lofty hill 

 •which rises to the south of the coast is composed of a talcous 

 schist, whose strata form with the horizon an angle of nearly 70°. 

 They dip to the south-west, that is towards the interior of the 

 island, and rise to the north-east, on the side of the sea. At 

 the foot of that hill, we see issuing from the sea, and rising up 

 against the mountains, beds of secondary limestone which are 

 inclined at an angle of 40°, but in a direction absolutely oppo- 

 site to that of the talcous schist, since they dip to the north- 

 east, and rise up to the south-west. When we view in profile 

 these two great formations, whose strata, opposed to each 

 other, display their sections above the soil and the heath, we 

 might fancy we saw two embattled troops in assault, with their 

 lances at rest against each other. The inclination of the beds 

 of talcous schist affords an exception to the general remark, that 

 primitive strata rise up against the centre of the chain or group 

 of mountains to which they belong. 



The rocks of the western part of Tor-nid-neon to the south- 

 east of Loch-Ranza, display a fine section of the junction of 

 schist with granite. The schist which occupies all the base of 

 that mountain, forms a part of that vast mantle of slaty rocks 

 which envelope the granitic region of Arran. The granite of 

 its summit is placed at the northern limit of that region ; it 

 rises far above the schist, and loses itself beneath its strata. 

 The slate on approaching the granite loses completely the ap- 

 pearance and nature of a talcous schist, and changes by insen- 

 sible gradations into clay-slate, (thonschiefer). The granite of 

 Tor-nid-neon is absolutely the same with that of Goatfield, and 

 of the other granitic mountains of Arran ; in large grains, the 

 feldspar being in great rhomboids, which give it a porphyritic 

 appearance, while the mica is black and scanty. The schist 

 dips to the north and rises up to the south, resting upon the 

 granite ; and nothing can be more distinct than the junction of 

 the two rocks. There is no transition, no passing of the one 

 into the other ; but they are as different at the point of con- 

 tact, as every where else. It is here that veins of granite of all 

 dimensions may be discovered issuing from the granitic mass 

 to enter into that of the slate ; cutting the folia of the latter in 

 various directions, and at various angles. In the spot where 

 the vein begins, the granite is in large grains, and differs in no 

 respect from the rest of the mass ; but in proportion as the vein 

 advances and becomes more slender, the grain grows propor- 

 tionally finer; as, if under constraint from the walls of ihe 

 vein, the elements of the granite had not been able to separate 

 and crystallize, as distinctly as in the other parts of the mineral. 

 Tiiere occurs also a remarkable change in the proportion of 

 these elements, according to their recedure from the mass of 



