408 
Farminr/ of Cormcall. 
store ewes ia lamb at the autumnal sheep-fairs* in the eastern 
parts of the county, which are fattened and sold the following 
year. Few oxen are kept — but chiefly cows — a great many of 
the old Cornish black breed, averaging from 18 to 25 per cent, 
on the acreage, being preserved here for their milking properties. 
The pigs are exceedingly good and plentiful, averaging from 35 
to 40 per cent, on the acreage. 
13. The Scilly Islands should properly be considered here. 
The soil is of the "growan" kind, commonly black peat, mingled 
with granitic particles, and frequently blown sea-sand ; in many 
places it bears fair crops of potatoes, barley, and sometimes 
wheat. The chief manure is sea-weed. The cattle, horses, and 
sheep are exceedingly small, being part of the native breeds of 
Britain preserved here in aboriginal purity. The pigs are nu- 
merous, and generally of a good description. This finishes our 
survey of the granite districts. 
Grautcacke Group. 
14. The country lying on the slate rocks is widely contrasted 
with that on the granite. The hills are smooth as if by art, and 
are so irregularly disposed, that they have not unaptly been com- 
pared to the waves of the sea, from their undulating character 
(33). Under the term "slate" we include all kinds of rocks, 
commonly so called, that are composed of sedimentary deposits, 
varying from the roofing slate even to a loose brown rubble, or 
becoming hardened, and so forming pudding-stones of great size. 
The colours are various — light grey, bluish grey, brown, whitish 
yellow, red and variegated — the red and variegated being gene- 
rally considered the most productive. Within these argillaceous 
masses are discovered products of fire in various places. In 
districts adjoining the granite, felspar porphyritic rocks (pro- 
vinciallv termed Ehans) traverse the slates in the form of dykes, 
varying from a few to 400 feet in breadth. The land where these 
elvans prevail is frequently covered by a thin layer of quartz frag- 
ments (provincially called spar), which abundantly traverse the 
slates in these districts. In other parts of the area we have igneous 
products which may properly be termed sedimentary, since "they 
appear to have been deposited in beds among the slates during 
their formation by the agency of water, after being ejected from 
fissures or craters in the shape of ashes or cinders, precisely as we 
might expect would happen at the present day with ashes or 
cinders discharged from insular and littoral volcanoes into the 
* T?ie principal she^p-iVns in Cornwall are held in the autumn, at Sum-, 
nieicouit, jMichell, and St. Lawrence ; at C'amelfoid, for early lambs, in 
July. T/ie large cattk-tiurs are held at Bodmin, Grampound, Probus, St. 
Lawrence, and Launceston. 
