Ch. V.] PRIMARY SCHISTOSE ROCKS. 81 



of accurate consideration, as they not only determine the con- 

 stitution of the most northern part of Europe, but furnish us 

 with information which can hardly be found either so full or 

 so distinct in the interior of mountains. 



The cliffs, and small islets on the shore, are not composed 

 of gneiss ; for the whole exterior of these rocks, their fine 

 slaty structure, and the earthiness of their cross fracture, pro- 

 nounce with distinctness that we are entering on clay-slate ; 

 but the shining surface of this rock resembles mica-slate : the 

 scales of mica, however, although abundant, are only scattered 

 on the continuous base of this slate. These strata contain 

 beds of massive brown quartz, in which delicate fissures are 

 frequently coated with chlorite, with occasional imbedded 

 crystals of felspar. Large folia of talc, and small greenish- 

 grey splintery cones, resembling serpentine, are not of uncom- 

 mon occurrence. 



Ascending Kielvigs-Eid we find small-grained granite, con- 

 taining insulated folia of black mica and a great deal of horn- 

 blende : the line of separation of these rocks may be followed 

 for a considerable length, and it may be clearly seen that the 

 clay-slate is continued beneath the granite. This granite 

 frequently changes itself into straight slaty gneiss, in which 

 large and beautiful garnets often occur. In some places, 

 however, this granite contains diallage and but little quartz ; 

 and by the former mineral gradually increasing, whilst the 

 quartz and mica continue to decrease till they disappear, the 

 granite becomes a fine granular greenstone without any visible 

 separation. This change in the nature of the rock is be- 

 trayed by weathering ; for the clove-brown diallage becomes 

 tile-red and frequently of a garnet colour. Towards the 

 mountains, this greenstone passes at last into a coarse granular 

 rock, in which the ingredients of felspar and diallage are 

 beautifully distinct, like the gabbro of the Italians. The 

 felspar of this variety more easily disintegrates than the dial- 

 lage, although the latter loses its colour sooner. The loose 

 blocks are therefore rough, the diallage projecting when the 



