Dr. Balfoub's Botanical Excursion. U<J 



various extent. We mado a few additions to the Flora of Cantyre on 

 the shores of the loch, by picking Milium effusum, Circaca intermedia, 

 and large specimens of Salix pentandra. 



I now proceed to give an account of our excursion in the island of 

 Islay, and in doing so I shall allude only to the more interesting Phan- 

 erogamous plants and ferns, inasmuch the mosses, lichens, and sea- 

 weeds observed by the party possessed no attraction as regards rarity. 



Islay is one of the western islands of Scotland, and was at one time 

 famous as the residence of Mac Donald, one of the great Kings of the 

 Isles. The holds or castles of the MacDonalds exist on islands in 

 some of the fresh water lakes to which I shall afterwards allude, espe- 

 cially Loch Gurim and Loch Fiulaggan. The extreme length of the 

 island, from the Moile of Oe in the south, to Rumhail in the north, 

 is about thirty miles ; and its breadth, from the point of Ardmore on 

 the east, to Sanig on the west, is upwards of twenty miles. The 

 superficial extent is about 154,000 acres, and the extent of coast is 

 nearly 200 miles. The form of the island is irregular, and it is deeply 

 indented by an arm of the sea called Lochindal. It is chiefly com- 

 posed of those hypogean rocks, termed by Lyell metamorphic, or 

 altered rocks, in consequence of the supposed changes which have 

 taken place in them since their deposition. These metamorphic rocks 

 contain few or no organic remains, and are thus separated from the 

 paheozoic stratified rocks. Clay-slate is looked upon as intermediate 

 between the metamorphic and the fossil iferous strata. The transition, 

 primary fossiliferous,and grauwacke of authors, are considered as belong- 

 ing to the pala30zoic series, being the strata which contain the fossil 

 remains of the earliest formed animals. The principal part of the island 

 of Islay consists of quartz rock, with beds of clay slate, grauwacke slate, 

 and micaceous schist. Quartz forms the high grounds of the north, and 

 the great mass of the Oe district. Gneiss occurs in some parts of the 

 island, and limestone in others. Porphyritic and basaltic rocks and 

 veins are met with in many places ; the basalt being often of an amyg- 

 daloidal nature. Near Port Askaig a peculiar kind of conglomerate 

 occurs. Lead and iron are found in the island, the former being 

 mixed with copper and some silver. At Ballygrant the lead is worked, 

 and the veins are tolerably productive. In the Rhins a vein of mag- 

 netic iron ore occurs, which, according to Mr. Campbell, contains a 

 small per centage of titanium. A rich ore of iron is found on Lossit 

 hill, and a vein of iron glance at Ballyneal. At Stramishmore, in the 

 Oe, there is a vein of impure graphite, 200 or 300 feet wide. Mr. 

 Campbell states that he has analysed this, and finds that the quantity 

 of carbon varies from 9 to 64 per cent., and iron from 5 to 16 per 

 cent He also has detected manganese in small quantity. Dr. R. D. 

 Thomson has examined two specimens of this impure graphite, and 

 the following are the results he has obtained : — 



