112 TRANSACTIONS, NATURAL HISTORY SOCIETY OF GLASGOW. 



present existence of alpine plants on these mountains. This 

 structure was caused by the intense folding to which the rocks 

 had been subjected, and by the development of a series of 

 minute divisional planes crossing the earlier foliation. The 

 efEect of these minute divisional planes was to make the schists 

 exceedingly friable, so that they became easily disintegrated, 

 and thus formed a suitable soil for the nourishment of the alpine 

 flora. Further, it was pointed out that' the importance of the 

 mechanical structure of the schists in the distribution of these 

 plants is conspicuously shown in the great cliffs of phyllite 

 covered with an exuberant alpine vegetation, and that upon 

 these cliffs many of the alpine plants are anchored like limpets 

 to a rock. 



There can be no doubt that this outcrop of schists has been 

 the most important factor in the determination of the present 

 distribution of our alpine flora. Other factors, however, enter 

 in, such as altitude, meteorological and physical conditions, (fee, 

 while the subject is further complicated when we bear in mind 

 that the Mamlom and Ben Lawers ridges must have acted as 

 secondary centres of dispersal from which these plants have been 

 distributed in the more immediate neighbourhood of these two 

 areas. Chemical analyses of typical specimens of the Ben 

 Lawers phyllite have been made by Prof. Sexton, of the Techni- 

 cal College, Glasgow, and, when these have been more fully con- 

 sidered, it is to be hoped that they will throw still further 

 light upon the part which these schists have played in the 

 distribution of the alpine plants. 



The President intimated that the statutory date of the meeting 

 of the Society not being suitable for a lecture on " Fresh-water 

 Algae," by W. West, Esq., F.L.S., he had made arrangements with 

 the Microscopical Society of Glasgow to have the lecture 

 delivered under their auspices on the date of their meeting, viz., 

 Tuesday, 14th April, at 8 p.m. 



28th Apru., 1903. 



Mr. Peter Ewing, F.L.S., President, in the chair. 

 Mr. Thomas Wishart, 234 Crown Street, Glasgow, was elected 

 an Ordinary Member. 



A report of the Society's excursion to Calder Glen was handed 



