Part II.

410 'Theory of the Earth,

less of different qualities, according to the na-ture of those schisti from which the soil isformed.

Such mountains are necessarily composedof rounded masses, and not formed of angulardrapes. They are covered with foil, whichis more or less either honey or tender, sterileor fertile, according to' the materials whichproduce that foil. The fertile mountains aregreen and covered with grafs; the sterilemountains again are black, or covered withheath in our climates.

Thus we have a general character of smoothand rounded mountains; and also a distinc-tion in that general character from the pro-duce of the soil indicating the nature of thesolid materials, as containing, either on theone hand calcareous and argillaceous sub-stances, or, on the other, as only containingthose that are micaceous and siliceous.

With regard again to the other species ofmountain, which we have termed rocky, wemust make a fubdistinction of those whichare regular, and those in which there is no re-gularity to be perceived. It must be plainthat it is only of those- which have regularity