174 TIJANSACTIONS AND PROCEEDINGS OF THE [Sess. LXlii. 



Linnhe. The geological formation of these districts has 

 not yet been mapped out in detail, except in the western 

 third of Ardnamurchan, which is composed of tertiary 

 basalts, gabbro, with some limestone. The other parts are 

 composed of schists, which, for the present, are named 

 Dalradian. The rounded and frequently terraced hills of 

 the basalts are readily distinguished from the bare rocky 

 schistose formation ; the latter having also a thin peaty 

 soil, generally covered with heather, while the former has 

 a deep soil covered with grass. 



The flora of the two formations also differs, not so much 

 in the presence or absence of particular species, as in the 

 degree of frequency at which many occur. In this respect 

 the flora of West Ardnamurchan more resembles that of 

 the islands of the Inner Hebrides which have a similar 

 formation, that is those from Mull to Skye. The most 

 striking differences in the floras are the preponderance of 

 Calluna, Erica Tcfralir, and U. cinerca, and the abundance 

 of natural wood on the schists. As the soil is more 

 productive on the basalts, trees have been destroyed to 

 a great extent for the sake of cultivation ; and this has 

 only been done in a small measure on the schists. In 

 addition, the formation of the latter is of a more irregular 

 character, giving better shelter for the growth of trees ; 

 and the wetter peaty soil is probably more suitable for 

 Bi'tula j^uhescens, the commonest of the native species. 

 The poverty of this soil is illustrated by the abundance of 

 Molinia. 



The only distinctive plant of the basalts appears to be 

 Ordbanche ruhra, but the presence in quantity of Trifolium 

 medmm, Anthyllis Vulneraria, Rosa s2nnosisswia , Galium 

 cerum, and Camjxmula roUmdifolia gives a distinctive 

 character in many parts to the flora. Limiting the 

 remarks to the immediate districts under consideration, we 

 have the following plants which have been found only in 

 West Ardnamurclian : — llanuncidns, scderattis, li. hidbosus, 

 Draha incana, Trifotium medium, Ruhus Lindleiamcs, R. 

 corylifolius, Galium horcale, Scahiosa arvensis (colonist), 

 J'elasites, Veronica Anagallis, V. Bcccahuiuja, Ordbanche 

 ridira, TAstera ovata, Orchifi incarnata, and tUircx distans. 

 The limestone is noticeal)le for the occurrence in quantity 



