290 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1909. 
A number of petrographic provinces outside of the United States 
may also be briefly indicated. One of the best known is that of 
southern Norway, which is prominent through the classic researches 
of Brégger, the rocks of which are characterized by high alkalis, 
especially soda, and the presence of many minerals elsewhere rare. 
This is possibly connected with the region of the Kola peninsula in 
northern Finland. The British Islands, with the Faeroes, Iceland, 
and probably Spitzbergen, form another well-defined province, the 
rocks of which resemble on the whole those of our Rocky Mountain 
region, though they differ in some respects. Leaving aside Germany, 
Austria, and France, each of which contains several petrographic 
provinces, the relations of which appear to be somewhat complex, in 
the basin of the Mediterranean we find at least three well-defined and 
quite distinct provinces. In the eastern part, including the Grecian 
Archipelago and parts of Asia Minor, the rocks are rather siliceous, 
with fairly high lime and rather low alkalies, soda dominating potash, 
‘so that dacites, andesites, and feldspar basalts are prominent. 
Hypersthene is here rather common. The Italian peninsula shows a 
second, very well-defined province, which embraces seven distinct 
voleanic centers along the west coast. The rocks of this are remark- 
able for their high content in potash, which at times reaches extraor- 
dinary figures, and leads to the abundant presence here of the 
mineral leucite, which is elsewhere decidedly rare. Lime is also 
rather high, while soda, iron, and magnesia are low. The other 
provinces of continental Italy have not been thoroughly studied and 
are less well known. In the western basin of the Mediterranean, in- 
cluding localities in Spain, Sardinia, some islands south of Sicily, 
and probably southern France, there appears to be a third province, 
which differs from the others in that soda is much higher and the 
more basic rocks (basalts) contain very large amounts of titanium, 
and in other ways. This last may be connected with a province in 
eastern Africa, running down the Great Rift Valley and including 
parts of Madagascar, in which rocks rich in soda are very common. 
A somewhat similar province appears to exist in New South Wales 
and Queensland in Australia. 
The descriptions just given, which are but the barest sketches of 
only some of those which are known, and with no reference to 
authorities, will serve to give an idea of some of the leading distin- 
guishing features of petrographic provinces, and how multifariously 
they are scattered over the earth’s surface. Their existence and dis- 
tribution indicate clearly that the underlying magma basins, or the 
sources from which the igneous rocks are immediately derived, are not 
everywhere uniform and alike, but that there exists a certain hetero- 
geneity in the nonsedimentary parts of the earth’s crust. It should, 
however, be noted that two provinces, though widely separated, may 
