350 vm. ALTITUDE OF SPECIES. 



meter ; partly also, they are estimates made on faith of general repute 

 respecting the heights of certain hills and passes. The greater portion 

 of these altitudes were ascertained in the years 1856 and 1857, by the 

 two parlies, working quite independently of each other; how far their 

 figures would correspond or conflict, not being at all known until thus 

 brought together in the printed list. 



At the upper part of the list, it will be seen, the altitudes for the Lake 

 province are always greater than those for the Humber, as set after the 

 same names of plants. This difference between the provinces might 

 lead to a false inference, if looked at without recollection that Scawfell 

 and other hills in Cumberland attain to much higher elevation than the 

 fells of Yorkshire, The figures for neither province can be deemed 

 sufficiently complete and precise, to give reliable evidence whether the 

 plants generally ascend higher in one province than in the other. 



A more satisfactory inference can be drawn from a comparison be- 

 tween the heights for North England and those given in ihe antecedent 

 list for the Grampian mountains in the middle of Scotland. At equal 

 altitudes on these latter mountains the flora is found to be much more 

 numerous than it is in the North of England ; many of the individual 

 species being also found to ascend to greater heights. These two facts 

 hold good until we descend to slight altitudes,— say, below 1000 feet; 

 where they are reversed, and the contrary becomes true. It is easy to 

 account for this exception to a more general rule, namely, that of spe- 

 cies ascending less high in a more northerly latitude. Like most 

 " exceptions " to well-founded rules, it is simply an example of one or 

 more other such rules or principles. The mountains of Scotland are 

 much more lofty than those of England ; and at or above equal altitudes 

 the extent of surface is far greater in Scotland. The higher elevation 

 affords suitable place and climate for various plants too alpine or arctic 

 for the lower hills of England. Besides this difference, there are com- 

 paratively sheltered glens or ravines, and extensive surfaces of rocks 

 almost inaccessible to sheep, situate among the Grampian mountains at 

 altitudes where in England only bleak summits are found, of very small 

 extent, and mostly close-cropped by flocks. In showing the number of 

 species ascertained at or above equal heights in the two tracts of country, 

 the subjoined table will evidence the influence of those differences on 

 the general flora ; while a comparison between the altitudes stated in 

 the two lists, for the same individual species, will equally serve to show 

 their usually higher ascent on the loftier hills of Scotland: — 



