30 The Great World's Farm 



they are poor in the necessary minerals to begin with, and 

 what they do possess is, as we have seen, dissolved, and 

 in great part washed away. Granite slopes are poor and 

 sandy, therefore, while the clay deposited at their feet is 

 too stiff and compact to be fertile; and nature seems to 

 tell the farmer as plainly as she can that in most cases he 

 will not find it worth his while to try and grow wheat 

 either on the hills or in the dales of a granite district. Of 

 course, where granite decays on the level, and its various 

 minerals remain, all crumbled down and mixed together, it 

 is naturally more fertile than where the best of them are 

 washed away; and thus we find that the granite soils of 

 the Scilly Isle are far more productive than those of the 

 Scotch hills, and are capable of bearing good crops of 

 corn, in part at least, because less of the potash has been 

 washed away from them. But some thanks are also due 

 to the more genial climate, for on the granite highlands of 

 Dartmoor there is no vegetation but heath and coarse 

 grass, and though one has heard of laborers attempting to 

 cultivate portions, and not without some success, it is 

 impossible to say that the soil is naturally adapted for 

 either field or garden crops. The moor is flat enough, 

 indeed, to prevent the separation of the sand and clay, 

 and such minerals as the granite possesses are fairly enough 

 mixed without much loss by washing; but the natural 

 poverty of the rock is aggravated by its elevated situation 

 on the one hand, and by the shallowness of the soil on the 

 other, and the soil therefore labors under the two great 

 disadvantages of a cold climate and want of drainage. 

 To the latter of these are due the many bogs which abound, 

 not only on Dartmoor, but on the granites of Scotland, 

 and the serpentine rocks of the Lizard as well. 



