90 Transactions of the 



wei.^ht ; the other is p;reenish black, with a lamellar structure, and is 

 translucent in thin sections, with a green tinge. Tiie surface of its 

 fracture is resinous. It is found about Balta. 



Potdone is found all around Balta ; and Porcelain earth or Kaolin, 

 is found on the western side of Bnrra Fiord, and occurs on the south 

 west Fetlar Island. This mineral is earthy, opaque, and dull, and 

 very friable. It is probably derived from the decomposition of the 

 gneiss. 



Alluvial Gold is said to have been discovered on a point of coast 

 to the east of Burra Fiord and there is good authentic evidence of its 

 occurrence here. On the shores of this fiord, I found some fine 

 varieties of granite. They were fragments of large waterworn pebbles, 

 di-ifted here from some foreign country, and contained large plates of 

 pure mica. Besides these, eurite and various porphyries are found. 



Magnetic and Bog Iron ore are found abundantly on Keen Hill, and 

 a dark ore, which I believe to be Hausmannile. I also found purple 

 crystals, probably of some manganic compound, but not having seen 

 their analysis, this is only conjectural. 



Botany. — The flora of Unst, as we might expect, is of a boreal 

 character ; its flowers are hardy and grow mostly in the rocky 

 ground, and though they are few in number yet they are interesting. 

 The first list of the plants of Unst was made by Thomas Edmonstone, 

 who discovered in his native island the Arenaria Norvegica, a flower 

 hitherto unknown to the British flora. The only spot in Great Britain 

 for this rare plant, is a bare and rocky piece of ground, at the south- 

 western foot of Keen Hill, on the northern side of Balta Sound. Jt 

 grows among the small and loose stones of serpentine, (it cannot 

 be called soil,) where even the grass will not thrive. It does not 

 exceed three inches in height, but has long roots. A species of 

 Arenaria, which is supposed to be the same as this flower, grows on 

 a cliff at Ben Bulben, in Siigo, Ireland ; but the Shetland variety is 

 distinguished by broader sepals and more succulent leaves. Its seeds, 

 probably, came here from Norway, and, thriving in the rock and sea 

 air, the plant has since continued to grow, but even in this locality it 

 is by no means abundant. 



A species oi Lgchnia grows in a 'chromate quarry' to the south of 

 Balta, aud the sea pink on Heog's Hills. The Linnea Borealis is 

 common all over the Island and grows chiefly on peaty ground. 

 Various sandworts are found on the beach in some of the sheltered 

 bays. Many other flowers occur, but of their names I am yet 

 ignorant. 



During my stay in Unst, I saw not a single butterfly, and the 

 lepidoptera are no doubt absent ; but the list of coleoptera is much 

 longer, and I counted several genera : the serpentine hills are the haunts 

 of a small red beetle, and the standing pools of water contain many 

 water-beetles. 



Marine zoology may be studied with advantage in Unst atcertam 

 seasons. Balta Sound is the most convenient for dredging in. Its 



