istence, denudation has left no vestiges of them at the present day.
In all these respects the resemblance of the volcanic phenomena to those
of Peninsular India is remarkably striking; it suggests the view that
they are contemporaneous as regards the time of their eruption, and
similar as regards their mode of formation.

[1] W. T. Blanford, _Geology of Abyssinia_, pp. 151-2.

[2] Blanford, _loc. cit._, p. 182.

CHAPTER III.

CAPE COLONY.

_Basalt of the Plateau._--The extensive sheets of plateau-basalt forming
portions of the Neuweld range and the elevated table-land of Cape
Colony, may be regarded as forerunners of those just described, and
possibly contemporaneous with the Ashangi volcanic series of Abyssinia.
The great basaltic sheets of the Cape Colony are found capping the
highest elevations of the Camderboo and Stormberg ranges, as well as
overspreading immense areas of less elevated land, to an extent,
according to Professor A. H. Green, of at least 120,000 square miles.[1]
Amongst these sheets, innumerable dykes, and masses of solid lava which
filled the old vents of eruption, are to be observed. The floor upon
which the lava-floods have been poured out generally consists of the
"Cave Sandstone," the uppermost of a series of deposits which had
previously been laid down over the bed of an extensive lake which
occupied this part of Africa during the Mesozoic period. After the
deposition of this sandstone, the volcanic forces appear to have burst
through the crust, and from vents and fissures great floods of augitic
lava, with beds of tuff, invaded the region occupied by the waters of
the lake. The lava-sheets have since undergone extensive denudation, and
are intersected by valleys and depressions eroded down through them into
the sandstone floor beneath; and though the precise geological period at
which they were extruded must remain in doubt, it appears probable that
they may be referred to that of the Trias.[2]

[1] Green. "On the Geology of the Cape Colony," _Quart. Jour. Geol.
Soc._, vol. xliv. (1888).

[2] The district lying along the south coast of Africa is described by
Andrew G. Bain, in the _Trans. Geol. Soc._, vol. vii. (1845); but there
is little information regarding the volcanic region here referred to.

CHAPTER IV.

VOLCANIC ROCKS OF PAST GEOLOGICAL PERIODS OF THE BRITISH ISLES.

It is beyond the scope of this work to describe the volcanic rocks of
pre-Tertiary times ov