398 



BOTANICAL GEOGRAPHY. 



The investigation of the real nature of our Indian fossil flora, has 

 now become a matter of parmouut interest. The instance above cited, 

 proves that the vegetation of these latitudes under certain eleva- 

 tions was, in one, and that a striking feature, at least analogous 

 to that which now exists. Further discoveries may prove the flora 

 of the globe at a certain remote period to have been entirely tropical. 



At any rate it is quite certain, that such floras of the now tropical 

 countries, were never boreal, or even temperate. 



It might not be amiss to notice here the article Botany in Murrays 

 Geography, so far as it relates to the Botanical Geography of the 

 East, 



The explanation of the height of perpetual snow therein given, 

 is wholly untenable, for were it true, the same line should 

 occur at a lower elevation on the north, than on the southern face, 

 and we know the contrary to be the case. We are then told that it is 

 partly due to the easy slopes of the Himalayan chain, and lastly, that 

 the Himalayan range partakes of the equatorial zone, in the charac- 

 ter of its climate and vegetation, that the lower plains of Nepal and 

 Bootan differ little from Hindostan in their vegetation." What we 

 are to understand by the vegetation Hindostan, is not explained, 

 although we know it to be various. 



Then we are told that no frost and snow is found in Bootan except 

 on the high mountains, although it is said to snow annually at Kat- 

 mandoo in similar latitudes, and at a very inferior elevation. Lastly 

 the ripening of grapes at such elevations at 8, 12000 ft. is at- 

 tributed to the immediate effect of solar radiation, which is said to be 

 more powerful as the intervening stratum of air is less thick and 

 more aerified. It should rather be said that the effect of the di- 

 rect rays of the sun is more intense under such circumstances, and 

 that radiation is less. Humboldt however, has given a more sa- 

 tisfactory explanation. The effect according to this philosopher is; 

 caused by radiation from the table land of Thibet, i. e. by mediate, 

 or indirect radiation. 



In the same work, a remark is made by Mr. Swainson from which 

 we are led to infer, that vegetables are less defined in their distribu- 

 tion than animals, and that hence the study of the distribution in 

 the higher branches of the organic kingdom, will give better results 

 than that of the lower. To this argument objections may be taken. 



