HOW TO MAKE A SMALL ROCK-GARDEN 81 



done. Some stones are hard, some soft ; some weather 

 readily, some take years to weather ; some break clean into 

 blocks or flags, and some only break into very rough 

 unshapely pieces. 



Some rocks contain many fossils ; these are interesting 

 to the collector, but they look odd and unnatural in a 

 garden. I once tried making a rock-garden with stones 

 full of visible fossils, but did not at all like its appearance. 

 Use unfossiliferous stones if possible, or arrange the stones 

 so that the fossils do not appear. 



As a general rule hard stone should be used, but not 

 too hard. Granite, Whinstone, Dolerite, Diorite, Slate, 

 Basalt, Gabbro, Trachyte, Felsite, Greenstone, and similar 

 rocks are not suitable for rock-garden construction, 

 although plants will be found growing fairly freely about 

 some of them in nature. Also such crystalline rocks as 

 Marble, Derbyshire Spar (Calcite), Gypsum, and Heavy 

 Spar, look unnatural. 



But over and above these there are still a good many 

 rocks to choose from. Some of these I give below : 



Sandstone : There are many sorts of this. Those 

 found in our own district, in the coal measures, are 

 eminently suitable for rock-garden making, but other 

 kinds will do. Avoid using red sandstone on account of 

 the iron it contains, millstone grit as being so extremely 

 porous, conglomerate and breccia for their unsightly 

 appearance, and inferior calcareous sandstone on account 

 of the rapidity with which it disintegrates. 



Shale : Sometimes shale is quite hard enough and 

 found thick enough to be used for rock-gardens. So long 

 as it is brown and fairly sandy it is quite useful ; but black 

 shale or red shale should on no account be used. Rough 

 pieces of Gannister may also be used, if nothing better is 

 available. 



Limestone : There are many kinds of this, but the hard 

 Derbyshire Limestone is, to my mind, the best. It is found 

 in many other parts of England, and where it is quarried 

 it is usually fairly cheap. Silurian Limestone, " Wenlock " 



