TRANSACl^IONS OF THE SECTIONS. 205 



Jew residiug- iu Morocco, so far as tliey rest oa personal knowledge, dessrve more 

 confidence. 



The following are the chief points as to which I think myself entitled to express 

 an opinion, premising that as to some of them I may place undue confidence in my 

 own personal conclusions : — • 



1. The portion of the Atlas chain that is seen from the city of Morocco is con- 

 siderably higher than has generally been supposed. The chief summits appear to 

 be nearly ot the same height, and the majority of these approach very nearly, if 

 they do not occasionally surpass, the level of 14,000 feet. Westward of the district 

 of Cxlaoui, S. W. of the city of Morocco, the range subsides gi-adually as it approaches 

 the coast. 



2. There is a certain amount of tolerable evidence tending to show that the 

 interior part of the range extending from the upper valley of the Wed Tessaout to 

 the frontier of Morocco contains peaks of higher elevation than any seen by us. 



3. The existence of an anti-Atlas or range parallel to the main chain, and 

 enclosing on the south side the great valley of the Sous, was established by Rohlfs, 

 if not by previous travellers ; but we are probably the first who have looked across 

 the wide intervening space and scanned the outline of the anti-Atlas. The portion 

 seen by us at a distance of from 50 to GO miles is far less bold in form than the 

 main range. The utmost height of that portion can scarcely exceed 10,000 feet. 



4. The map compiled by Capt. Beaudouin, and published in Paris at the D^pot 

 Geni5ral de la Guerre in 1848, which is decidedly the best that has hitherto 

 appaared, is defective in representing the main chain as arising abruptly from the 

 low country, scarcely indicating considerable lateral valleys. At the sanie time it 

 should be remarked that the projecting ridges which divide these lateral valleys 

 appear to be lower, in comparison with the peaks of the main chain, tlian is usual in 

 other great mountain-ranges. 



5. There is a marked tendency to the formation of considerable valleys parallel to 

 the main chain, and in such cases the remark made in the last paragraph does not 

 apply. Some of the higher peaks, and amongst them that named Miltsin by the 

 late Captain Washington, lie in ridges nearly parallel to the main chain. 



6. It appears at least possible that the anti-Atlas, if we may so denominate tho 

 range forming the southern boundary of the Sous valley, is merely an example on 

 a large scale of one of the parallel ridges just referred to, many examples of which 

 are to be found in better known mountain-regions. 



7. The existence of two parallel chains so continuous as those represented in 

 Gerhard Rohlfs's map appears 'to be open to reasonable doubt. In the absence of 

 direct evidence, it appears at least equally probable that the conformation of the 

 main chain may be best represented by a series of ridges slightly inclined to the 

 axis of elevation of the entire mass. 



8. The remarkable valley of the Benimguald, laid down on Beaudouin's map as 

 extending more than one hundred miles from S.E. to N.W. in a nearly direct line, 

 must be pronounced imaginary or based on false information. Tlie details "iven in 

 llohlfs's ' Ileise durch Marokko,' however incomplete, are manifestly inconsistent 

 with the general plan of the mountain-system laid down in that map. 



On tlie OeograpMcal Distribution of Forests in India. Bi/ Dr. Brandis. 



In all countries the character of forest vegetation mainly depends on soil, climate, 

 and the action of man. In India the greater or less degree of moisture is perhaps 

 tlie most important element in this respect. Moisture and rainfall are not identical 

 terms. In many parts of India and elsewhere dew and the aqueous vapour 

 dissolved iu the atmosphere, or the water derived from the overflow of rivers and 

 from percolation, are sources of moisture as important for the maintenance of arbo- 

 rescent vegetation as the fall of rain and snow. It would greatly facilitate the 

 labours of the forester and of the botanist, who inquire after the geograpliical distri- 

 bution of forest-trees, if the amount of atmospheric moisture and the formation 

 of dew during the seasons of the year in different p arts of India had been sufficiently 

 studied ; but in the present state of our knowledge we must be satisfied with dividino- 



1872. 15 



