FLORA OF ARRAN. 229 



plains, hot and sheltered glens, damp woods, and sandy sea- 

 shores. We have every kind and degree of exposure, from 

 the wind-swept top of Goatfell to the warm hollows of Glen 

 Cloy, and this within the compass of a few miles. We have 

 modern fir-plantations and natural birch woods; cultivated 

 fields and hedge-rows ; wide stretches of peat- bog ; rocky pro- 

 montories and caves; open strands and sand-hills. Of soils, 

 too, in the stricter sense of the word, there is a notable 

 variety. The general division of earths into sandy, loamy, 

 clayey, and so forth, is loose, and for scientific purposes inac- 

 curate ; distinctions far more natural, as well as valuable, are 

 furnished by the nature of the rocks, whose decomposed 

 materials form the soil. In Arrau the variety of the geo- 

 logical formations produces a corresponding diversity in the 

 composition of the earths; and though we are no doubt still 

 greatly in the dark as to the influence of soil on the habitat 

 of plants, there can yet be little doubt that the diversity of 

 soils furnished by the granites, traps, porphyries, slates, sand- 

 stones, shales, and limestones, must exercise a powerful 

 influence on the flora. Whatever may be the importance of 

 these conditions generally, they certainly exist here in a 

 remarkable degree. 



To these advantages of geographical position and physical 

 character is to be added the scarcely less important one of 

 climate. Lying off the west coast of Scotland, aud thus almost 

 in the Atlantic, Arran enjoys a copious rain-fall, while its 

 insular position preserves it from those extremes of heat and 

 cold which are so injurious to vegetation. Hence it is that 

 the climate, while in many parts quite cold enough for the 

 ordinary plants of Britain, and while the mountains rise high 

 enough to be a fit habitation for several alpine species, is yet 

 sufficiently mild and equable for the growth of some usually 

 found in more southerly regions. These conditions exist also 

 in the extreme point of Cantire; and accordingly we find 

 Campbelton enjoying the mildest winter in Scotland, and 

 many tender species flourishing there in the open air. 



