I2s^TliODUCTORY. 27 



where this tree grows is there any of the trap formation. 

 With the exception only of this volcanic rock, the Sal 

 appears to thrive on any other formation, being equally 

 abundant within its own area, where primitive rocks, or 

 sandstones, or lateritic beds predominate. Thus I 

 believe that the Sal, where the soil is suitable — that is, 

 where there are no trap rocks — has exterminated the 

 Teak, of which it is a natural rival. In other parts of 

 India, where the Teak does not meet with this rival, as 

 in Malabar and Burma, it flourishes on the soils from 

 which it is here excluded by the Sal. The general con- 

 clusion appears irresistible, but sharp contrasts perhaps 

 best illustrate such peculiarities. Many such might be 

 mentioned, but two in particular are very noticeable. 

 Within the Sal region, in the hills immediately to the 

 east of the town of Mandla, there is a considerable area 

 covered by Teak, to the total exclusion of the Sal. The 

 whole of this region is composed of a trap overflow ; and 

 all around it, as soon as the granitic and lateritic forma- 

 tions recommence, the Sal again entirely abolishes the 

 Teak. Again, within the area of the trap and Teak, in 

 the valley of the Denwa river, 150 miles west of the 

 furthest limit of the general Sal region, is found a soli- 

 tary isolated patch of the latter, occupyiug but a few 

 square miles. Here the Sal grows on a sandstone 

 formation. It is surrounded on three sides by trap 

 rocks, and there it entirely ceases, and is supplanted by 

 the Teak as the principal timber tree. But how^ to 

 account for this small and unimportant outlier of the 

 great Sal belt ? To maintain our theory, some link to 

 connect them together should be found. I think that a 

 hypothesis, much less extravagant than many which are 

 introduced into such arguments, will do so. Towards 



