It is of a darker colour, and forms more into clods to retain moisture.

I may here mention that the Himmalaya chain does not abound in volcanic rocks, like the chains of Central and Southern India; and that the soils, which are formed from its detritus, contain, in consequence, less phosphoric acid, and is less adapted to the growth of that numerous class of plants which cannot live without phosphates.

The volcanic rocks form a plateaux upon the sandstone, of almost all the hills of Central and Southern India; and the soil, which is formed from their detritus, is exceedingly fertile, when well combined, as it commonly is, with the salts and double salts formed by the union of the organic acids with the inorganic bases of alkalies, earths, and oxides which have become soluble, and been brought to the surface from below by capillary attraction.

I may also mention, that the basaltic plateaux upon the sandstone rocks of Central and Southern India are often surmounted with a deposit, more or less deep, of laterite, or indurated iron clay, the detritus of which tends to promote fertility in the soil.

I have never myself seen any other deposit than this iron clay or _laterite_ above the basaltic plateaux.