522 Mr. Hinds on Climate in conneocion 



are such active agents in the generation and increase of soil 

 as is generally allowed ; and for the reasons, that under a va- 

 riety of chmates and circumstances I have never witnessed 

 the process in any extent, and can see no correspondence be- 

 tween cause and effect. If a tract of rocky country were left 

 in the undisturbed possession of a multitude of lichens, I feel 

 confident we might wait for a space bordering on eternity be- 

 fore anything like productive soil would appear. If there are 

 any plants more conspicuous than others for this kind of in- 

 fluence I believe them to be grasses ; for they are to be seen 

 clothing the black weather-worn volcanic mountain ridges of 

 the different groups of islands in the Pacific Ocean, to the al- 

 most total exclusion of everything else, and entirely covering 

 the exposed shoulders of many of the hills, which consist 

 nearly altogether of lava rocks. In the numerous singular 

 coral islands grasses are the first to prepare the way for the 

 herbaceous vegetation, and in a number of other islands, as 

 the inhospitable St. Paul's, there is little other vegetation than 

 grass or reeds. Scattered about the world are many small 

 dreary rocky islets, which lift their solitary heads a few feet 

 above the extensive waste of waters around them. If the 

 chinks and crevices of these are examined, they will usually 

 be found to contain a little starved grass and a few stunted 

 bushes. The mode of growth of these grasses is peculiar, and 

 perhaps suited to their situation. Each plant forms a sepa- 

 rate and independent tuft, which, whilst it preserves in its 

 centre the active functions of life, increases from the exterior, 

 and often attains such a size as to impede the surface. Grasses 

 seem to me to be usually the earliest plants to occupy waste 

 grounds, but an active rivalry is sometimes displayed in nearly 

 all that class of plants, which, sending a taper root downwards, 

 spread their branches horizontally in a gradually dilating cir- 

 cle. If lichens are really so efficient to this end, the Roccella 

 tinctoria ought, long before this, to have reclaimed the barren 

 Dejertos to something of the rich fertility of their beautiful 

 neighbour, Madeira; and sheep are pastured here during 

 certain times of the year on their spontaneous grasses. 



The chief portion of the soil of the rich and fruitful parts of 

 the globe will be found to exist about the deltas of rivers, in 

 plains, or in valleys, or some other situation where it is pro- 

 bable it has one time or other been deposited by water. Bear- 

 ing in mind the twofold nature of soil, the inorganic portion 

 has not, as a general rule, resulted from the disintegration of 

 subjacent rocks ; but in the abrasion, by moving water and the 

 substance hurried with it in its course, of the channels of 

 mountain streams, cascades, and the torrent courses of the 



