Cornwall, Dcroii, and West Somerfiet. 31 



Dr. Paris has pointed out that the relative fertility of the gra- 

 nitic soil of Cornwall would appear greatly to depend upon the 

 abundance and easily-decomposable character of the felspar in 

 the subjacent rock ; and he has also remarked that the relative 

 proportion of mica would seem to have an appreciable effect upon 

 such soils^ tending to render them poor, while the iron in some 

 may become a useful element in them.* Our own observations 

 would tend to confirm this view, due allovv^ances being made for 

 exposure to atmospheric influences. These would, however, seem 

 very considerably to influence the agricultural character of the 

 granitic or growan soils,f as they are generally termed. For 

 instance^ we have been unable to detect any appreciable difference 

 between much of the granite on the high land of Dartmoor and 

 that in the Scilly Islands, in places where both were well decom- 

 posed. In the Scilly Islands, particularly in St. Mary's, there 

 is much growan land which is fairly fertile, producing good crops 

 of potatoes, wheat, barley, and grass, while Dartmoor is merely 

 covered by heath and coarse grass, and peat is abundant. In 

 one case we have islands in the Atlantic of small relative height, 

 and upon which it is rare to see snow ; while in the other there is 

 an extensive area in the interior, varying from 1400 to 2000 feet 

 above the sea, on which fogs are frequent, and snow often falls and 

 rests before it is seen on the lower grounds. The country around 

 Moreton Hampstead, several hundred feet lower than the mass of 

 Dartmoor, of which it is the geological continuation, being com- 

 posed of a portion of the same mass of granite, forms a striking 

 contrast as to fertility with the high land on the west of it. The 

 grass land is generally good, tolerable crops of barley are ob- 

 tained from it, and the potatoes grown are very highly esteemed 

 and readily purchased at the Exeter market, one to which the 

 products of many fertile lands are brought ; yet the general cha- 

 racter of the granite round Moreton Hampstead, and of that upon 

 much of the adjoining high land of Dartmoor, is mineralogically 

 the same. 



Judging from Devon and Cornwall, there are few soils which 

 are more affected by relative elevation above the level of the sea, 

 in the climate there found, than the growan, or granitic soils. 

 No doubt there may be some variation in the mineralogical cha- 



the Lizard, Dr.Borlase notices that in his time barley had been sown, and 

 that " in nine weeks commonly, oftentimes sooner, they have had it again in 

 the sack, fit for market. This quick return,' he continues, " is not owing 

 to any particular sort of barley, but to the soil and situation, and a kindly 

 warm season, the nights in the summer time on the sea-coasts being seldom 

 or ever cold." — Natural History of Cornwall (1758), p. 87. 



* Trans. Geol. Soc. of Cornwall, vol. i., pp. 173, 174. 



t Growan is the Cornish name for gravel. 



