490 R. H. RASTALL 
contain wolframite, most abundantly in a comparatively narrow 
zone near the granite-slate contact. Arsenopyrite is also abundant, 
and in the upper parts of the lodes, farther away from the granite, 
tin gradually gives place to copper. Other metals, such as 
molybdenum, silver, antimony, bismuth, and uranium, are also 
found, while lead and zinc are abundant in a later series of lodes, 
usually more distant from the contact. Among the gangue minerals 
tourmaline, topaz, and fluorspar are abundant. Here the con- 
nection of the tin-copper mineralization with the granites and their 
pneumatolytic phase is obvious. The age of this is also definitely 
fixed, since the granites cut Upper Carboniferous rocks and the 
Permian strata are not metamorphosed. The whole of this igneous 
cycle is a direct consequence of the Armorican crust disturbances 
which had such an important influence in molding the geological 
structure of west-central Europe. Very similar phenomena are to 
be seen in Brittany, in Spain and Portugal, and in the Erzgebirge 
on both sides of the frontier between the German Republic and 
Czecho-Slovakia: all of these are broadly contemporaneous with 
the similar occurrences in Cornwall. 
Here we have a clear example of a metallogenetic province, 
showing a definite association of mineral deposits of a peculiar 
type with a phase of igneous intrusion dependent on a particular 
set of earth movements. The number of metals present is very 
large, but the most characteristic are tin and tungsten, and a 
special feature observed in Cornwall, Bohemia, and Portugal is 
the presence of uranium. 
Turning now to another region of the Old World, we find a 
great development of tin ores in the Malay peninsula, in Banka 
and Billiton, and on the eastern side of the Australian continent 
from Queensland to Tasmania. In Lower Burma (Tavoy) we 
find a little tin and much tungsten, so that this evidently forms a 
slightly varying extension of the same field, a local facies. This 
tin-bearing region stretches parallel to the great Malayan arc 
and its continuation into Australia and the mineralization is 
closely connected with the intrusion of granites, probably of 
Permo-Carboniferous age. Furthermore, this great province is 
divided up into subprovinces characterized by special mineral 
