THE ROCK GARDEN 



101 



ROCKS AND STONES 



The best effect is obtained by using stones from the place itself or a 

 nearby source as their color and formation will be quite naturalistic. 

 Select those that have been lying on the surface and have an old, 

 weather-beaten appearance. They will, of course, be of all sizes; the 

 average size will depend on the size of the rock garden. A large 

 garden demands large stones, but even in a small garden a few large 

 st6nes help the appearance wonderfully. It is also wise to select a 

 type of stone that does not crumble easily and then keep to the one 

 kind throughout the garden. The two chief classes of rock are igneous 

 and stratified (Fig. 91). The former is recognized by the irregular 

 shape of its fragments and the fact that no layers are seen in its 

 formation — granite is a good example of this type. The other may 

 be recognized immediately by the parallel, horizontal lines, which 

 form the strata of the stone. These are seen very clearly in limestone 

 rocks, shales, etc. 



The two important styles in rock gardening are the outcome of 

 the use of the two widely different forms of stone described above. 

 If the stratified stone is used, the rock garden should be arranged to 

 follow that stratification throughout the garden in "uniform irregu- 

 larity." That is, the one _ 

 plane of stone, although 

 broken in various places, 

 should be seen right 

 through the garden. This 

 does not mean, however, 

 that all stones should be 

 laid on the same lines 

 and angle. In Nature, 

 large pieces are broken 

 off outcropping ledges by 

 natural forces, with the 

 result that the dislodged 

 pieces tumble down in 

 any position, but the 

 unity is still apparent in 



the stratification and , ^ -r-, t 



cleavage. In buildmg O 



the rock garden this ef- Fig. 91.— The two chief classes of rock 



Slr(3.Li fied- ^Lor^cz. ■ 



