predominate; 6000 ft. of limestone are found at Eureka, Nevada,
beneath 2000 ft. of shale. On the Pacific coast metamorphism of the
rocks is common, and lava-flows and tuffs occur in them.

In Canada, besides the occurrences previously mentioned in the eastern
region, Devonian strata are found in considerable force along the
course of the Mackenzie river and the Canadian Rockies, whence they
stretch out into Alaska. It is probable, however, that much that is
now classed as Devonian in Canada will prove on fossil evidence to be
Carboniferous.

_South America, Africa, Australia, &c._--In South America the Devonian
is well developed; in Argentina, Bolivia, Brazil, Peru and the
Falkland Islands, the palaeontological horizon is about the junction
of the Lower and Middle divisions, and the fauna has affinities with
the Hamilton shales of North America. Nearly allied to the South
American Devonian is that of South Africa, where they are represented
by the Bokkeveld beds in the Cape system. In Australia we find Lower
Devonian consisting of coarse littoral deposits with volcanic rocks;
and a Middle division with coral limestones in Victoria, New South
Wales and Queensland; an Upper division has also been observed. In New
Zealand the Devonian is well exposed in the Reefton mining field; and
it has been suggested that much of the highly metamorphosed rock may
belong to this system.

_Stratigraphy of the Old Red Sandstone Facies._

The Old Red Sandstone of Britain, according to Sir Archibald Geikie,
"consists of two subdivisions, the lower of which passes down
conformably into the Upper Silurian deposits, the upper shading off
in the same manner into the base of the Carboniferous system, while
they are separated from each other by an unconformability." The Old
Red strata appear to have been deposited in a number of elongated
lakes or lagoons, approximately parallel to one another, with a
general alignment in a N.E.-S.W. direction. To these areas of deposit
Sir A. Geikie has assigned convenient distinctive names.

In Scotland the two divisions of the system are sharply separated by a
pronounced unconformability which is probably indicative of a
prolonged interval of erosion. In the central valley between the base
of the Highlands and the southern uplands lay "Lake Caledonia." Here
the lower division is made up of some 20,000 ft. of shallow-water