ther eruptives. Their geological history may be
summarised as follows

The Himalayan area in pre-Cambrian times was, in its southwestern
extension, part of the floor of a sea which covered much of what
is now the Indian Peninsula. In the northern shallows of this sea
were laid down beds of conglomerate, shale, sandstone and
limestone, derived from the denudation of Archaean rocks, which,
probably, rose as hills or mountains in parts of Peninsular India
and along the Tibetan edge of the Himalayan region. These beds
constitute the record of the long Purana Era[1] and are probably
coeval with the Algonkian of North America. Even in these early
times volcanic disturbances affected this area and the lower beds
of the Purana deposits were penetrated by volcanic outflows,
covered by sheets of lava, uplifted, denuded and again submerged

[1] See footnote, p. 139.

134

beneath the waters. Two such periods of instability have left
their records in the sediments of the Purana sea.

The succeeding era--the Dravidian Era--opens with Haimanta
(Cambrian) times. A shallow sea now extended over Kumaun, Garwal,
and Spiti, as well as Kashmir and ultimately over the Salt Range
region of the Punjab as is shown by deposits in these areas. This
sea was not, however, connected with the Cambrian sea of Europe.
The fossil faunas left by the two seas are distinct.

After an interval of disturbance during closing Haimanta times,
geographical changes attendant on further land movements
occurred. The central sea of Asia, the Tethys, extended westwards
and now joined with the European Paleozoic sea; and deposits of
Ordovician and Silurian age were laid down:--the Muth deposits.

The succeeding Devonian Period saw the whole Northern Himalayan
area under the waters of the Tethys which, eastward, extended to
Burma and China and, westward, covered Kashmir, the Hindu Kush
and part of Afghanistan. Deposits continued to be formed in this
area till middle Carboniferous times.

Near. the close of the Dravidian Era Kashmir became convulsed by
volcanic disturbance and the Penjal traps were ejected. It was a
time of worldwide disturbance and of redistribution of land and
water. Carboniferous times had begun, and the geographical
changes in

135

the southern limits of the Tethys are regarded as ushering in a
new and last era in Indian geological history the Aryan Bra.

India was now part of Gondwanaland; that vanished continent which
then reach