The Karoo System or Karoo Sequence, is a geologic system of rock formations covering 1 500 000 square km and extending from the Equator

Equator

An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....

 south to the Cape of Good Hope

Cape of Good Hope

The Cape of Good Hope is a rocky headland on the Atlantic coast of the Cape Peninsula, South Africa.There is a misconception that the Cape of Good Hope is the southern tip of Africa, because it was once believed to be the dividing point between the Atlantic and Indian Oceans. In fact, the...

. The Karoo System spans a period of about 100 million years, starting from the Permian

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

 or Carboniferous

Carboniferous

The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...

 Period (c300 million years ago) to the Late Triassic

Late Triassic

The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...

 Epoch (228-200 million years ago).

The geology of the Great Karoo

Karoo

The Karoo is a semi-desert region of South Africa. It has two main sub-regions - the Great Karoo in the north and the Little Karoo in the south. The 'High' Karoo is one of the distinct physiographic provinces of the larger South African Platform division.-Great Karoo:The Great Karoo has an area of...

 consists largely of horizontally-bedded shales

Shalës

Shalës is a municipality in the Elbasan District, Elbasan County, central Albania. The municipality consists of the villages Shalës, Licaj, Kurtalli, Xibrake, Xherie and Kodras....

 and sandstones. Their uniformly level appearance is broken only by numerous igneous intrusions of dolerite dyke

Dike (geology)

A dike or dyke in geology is a type of sheet intrusion referring to any geologic body that cuts discordantly across* planar wall rock structures, such as bedding or foliation...

s and sills

Sill (geology)

In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or even along the direction of foliation in metamorphic rock. The term sill is synonymous with concordant intrusive sheet...

 producing the characteristic Karoo hills. Along the south-western and southern edges of the ancient basin, the massive ranges of the Cape System are prominent boundary features. In the south-west the Cederberg

Cederberg

The Cederberg mountains and nature reserve are located near Clanwilliam, approximately 300 km north of Cape Town, South Africa at about . The mountain range is named after the endangered Clanwilliam Cedar , which is a tree endemic to the area. The mountains are noted for dramatic rock...

 and Cold Bokkeveld ranges stretch for some 800 km to the Gamtoos River

Gamtoos River

Gamtoos River formed by the Kouga and the Groot is situated in the Eastern Cape Province of South Africa and is approximately 645 km long with a catchment area of 34,635 km²...

.

This vast inland plateau is at an elevation of between 600 and 1350 metres. Underground brackish water

Brackish water

Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...

 is accessible to stock-farmers by drilling of boreholes and the erection of windpumps. Soils are generally fertile though shallow, yielding good crops, especially along river-banks.