ROCK SALT. [Sontuu.] ROCK-WOltK, in gardening, an elevation, composed of earth and other loose materials, and covered with stones and fragments of rock, ka, amongst which plants adapted for such a situation are grown. When the rock-work is managed skilfully, and in accordance with surrounding objects, it may be made to add much to the beauty and interest of the garden. In the first place a proper situation should be selected, and the diameter of the rocks should harmonise with the situation. Simple outlines and surfaces not broken into fantastic shapes, are best suited to show off the plants. The best stones for rock-work are those which resist the action of the air, and they may be selected according to convenience from the rocks of the neighbour bend in which they are used. The most irregular ought to be chosen, especially tnose with cavities in them, which may be tilled with earth for the growth of mosses, ferns, and small plants. Frequently atones
are met with covered with lichens, which, from their picturesque colour., have a pleasing effect. Of these, the Lieken airollarus, yecu,ra rAiens, rentosoa, perellus, and sfellaris, are most common. Such stones are meetly large, and are best adapted for the base of the rock work.
Although rock-work is intended to present a mountainous or rocky vegetation In a small space, yet there are many circumstances that prevent the growth of true mountain and rock plants in such a situa tion ; but the dry ridges of earth and stones of which it is composed afford a favourable Situation fur the plants that chiefly occupy the dry soil of plains. On this account, small shrubs and creeping plants of any kind that will grow in a dry soil are selected for rock-work. Of these, the varieties are numerous, and the taste and care of the culti vator may be advantageously shown in the selection.