Notices of Memoirs — Bristol Naturalists^ Society. 229 



II. — The Geological Relations op the Alpine Flora of Great 

 Britain. By the Rev. J as. M. Crombie. 



(A paper read before the Geologists' Association of London.) 



IN tliis paper Mr. Crombie discusses the origin of the Alpine (or 

 Boreal) Flora of Great Britain, showing that it is directly due 

 to a past geological condition of our island. This Alpine Flora is 

 met with upon our higher moimtains ; but only on the higher ranges 

 of Scotland, on the lofty and extensive Grampians, does it occur in 

 great plenty and variety. 



The limits within which the plants are usually found are from 

 about 1,506 to 4,406 feet (the summit of Ben Nevis). This space 

 has been divided into certain zones, both physically and botanically, 

 distinct from each other, and these are applicable to all the loftier 

 mountains, making due allowance for diversity of situation, 

 mineralogical structure, etc. 



The flora of each is so similar in its main features as clearly to 

 betray a common origin and a similar mode of distribution. 

 Between our Alpine Flora and that of Scandinavia there is a great, 

 similarity, and the author considers that the boreal forms of Great 

 Britain were derived from it. 



He agrees with the late Professor Edward Forbes that the distri- 

 bution of this Alpine Flora was effected during the Glacial epoch, 

 which, indeed, the character of the plants themselves renders most 

 probable. 



III. PBOCBEDrNGS OF THE BbISTOL NaTURALISTS' SoOIETY. Vol.' IV. 



For the year 1869. 



IN their Report of 1869, the Council of the Society regret to state 

 that, although a fair amount of work has been done during the 

 year, yet there has been but a poor attendance of members, both at 

 the general Evening Meetings, and at the Summer Excursions. The 

 number of members has also decreased from 215, in 1868, to 167, in 

 1869 ; in addition to which however there are seven Lady Associates. 



In the present volume there are eleven papers, including some on 

 Geological subjects. 



There is an Analysis of the Report presented by the late Prof. W. 

 Hopkins to the British Association, " On the Theories of Elevation 

 and Earthquakes," by the President of the Society, Mr. W. Sandersj 

 F.R.S., etc. 



The Rev. Canon Moseley, F.R.S., Vice-President, communicates a 

 paper " On the Cause of the Descent of Glaciers." *' 



He considers that a glacier would not by its weight descend. As 

 glaciers move faster by day than by night, and faster in summer 

 than in winter, he maintains that it must be the variation in the 

 amount of solar heat which causes the changes of glacier motion. 



His theory is, that dilatation and contraction of the ice, produced 

 by the passage into it and withdrawal from it of the sun's rays, is 

 tho proximate -cause of the descent of glaciers. 



