S54 MINERALOGY. 



Mineralogy of Scalloway Roads^ I found a micaceous rock, forming the 

 Shetland. shore for a considerable way, in which there were no 

 particles of quartz visible: it was formed of thin plates 

 somewhat bent or undulated. This kind is reckoned, I 

 believe, very rare ; the fresh fracture, if I was not de- 

 ceived, had somewhat of a silky lustre, and the rock was 

 uncommonly tough. x 



Part of Scalloway Roads, especially toward the west, 

 is surrounded by micaceous rocks. From Mr. Scott's 

 house, quite through the valley of Tingwall, the general 

 rock is limestone, in which are no vestiges of any marine 

 production, and which, from its vicinity on each side of 

 the valley to micaceous rocks, I suppose, is 'primary. 

 These limestone strata were in most places highly in- 

 clined. This valley is the finest in Shetland, both for ex- 

 tent and cultivation. There are two lakes in the midst 

 of it ; one of which is said to be fifty fathoms deep. 

 Observe a rude pillar of a single block of granite erected 

 near one of these lakes. Probably it is a Scandinavian 

 monument. Ploughs arc more used in Tingwall-parish 

 than in any other part of these islands. All I saw had 

 only one stilt, like the Orkney plough. The spade 

 is much used in Shetland instead of the plough. The har- 

 rows I saw here had iron teeth on one side, and wooden 

 teeth on the other. 



After traversing half of this valley, ascend the hills to 

 the eastward for Lerwick. Observe fragments of mica- 

 ceous schistus and granite, as we ascended. Descend to- 

 ward Elsvoe, by a steep road, where micaceous rocks 

 were prevalent. Observe near the road a vein of whinm 

 stone traversing these rocks ; it was visible but for a short 

 way; it was dense, and dark-coloured. Ascend from 

 Elsvoe a steril hill of micaceous schistus ; pass several 

 ridges of mountains covered to a great depth hy peat- 

 moss, which concealed all that could interest a mineralo- 

 gist. On the top of a high hill, find great numbers of 

 rounded nodules of granite, quartz, and micaceous rocks, 

 which the rains have probably separated from a very 

 coarse sandstone breccia, of which this hill is composed. 

 This breccia appears at the surface, as we approach Ler- 

 wick, taking place of the primary rocks. The included 



nodules 



