NATURAL HISTORY SOCIETY OF GLASGOW. 227 



gales, and, as a consequence, few trees have been able to obtain a 

 foothold, and even these few owe their scraggy existence to their 

 being sheltered by walls or other artificial protection. The 

 phanerogamic flora of the island consists nearly altogether of 

 dwarfed shrubs and herbaceous plants, such as — Vaccinium Vitis- 

 Idaea, Arctostajihylos Uva-ursi, Juniperus nana, Ranunculi, 

 orchids, grasses, etc. The hills, or knolls rather, also present a 

 bare and rugged, uninviting appearance, so you will thus under- 

 stand that to the inexperienced botanist, the island presents a 

 very unpromising look when first sighted; but, as the sequel will 

 show, appearances here, as elsewhere, are sometimes deceptive. 



The rocks of which almost the whole of the island is composed 

 are gneiss, nearly, if not all, metamorphic conditions of hornblende, 

 &c, belonging, I believe, to the Upper Laurentian system. 

 In section they present generally a series of light and dark bands, 

 rather coarse-grained, which are so constantly varying in thickness 

 and structure that no two specimens are exactly alike. Sometimes 

 beds or veins of a different and, occasionally, more homogeneous 

 structure occur, as serpentine, felspar, hornblende, and quartz. At 

 Acha Mill there is an extensive ridge of almost pure quartz, which 

 has such a tempting look that it was quarried, and an endeavour 

 made to prepare it for monumental purposes, but, as might have 

 been anticipated from its structure, the attempt failed, and so the 

 ridge is still left to adorn the landscape. I noticed the veins of 

 hornblende on the west coast, not very far from the school-house. 

 The sea had not long left off the work of hewing down its rocky 

 barrier, the wind was pleasantly refreshing as it came from the 

 Atlantic, and the air was flooded with sunlight when I first saw 

 them, and as they glittered in the noon-day sun one could easily 

 imagine each crystal a gem, and the spot a veritable El Dorado! 

 The rocky knolls, with which the north end of the island is covered, 

 have that peculiar rounded and polished appearance said to be due 

 to the abradina; action of moving ice. 



Somewhat extensive accumulations of blown sand occur, 

 principally along the west coast, and in the hollows which have been 

 scooped out by the wind great quantities of land and marine 

 shells are found indiscriminately mixed up. The land shells consist 

 mainly of Helix nemoralis and Bulimics acutus, and the marine 

 shells, of Patella and Littorina. As the shells become decomposed, 

 the calcareous matter gets mixed up with the sand, and being of a 



VOL. IV. Q 



