Page 6 - Bulletin 2 1998

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The Early Pliocene Epoch (5,5 – 4 million years ago)

Above the Miocene sediments at Langebaanweg, is the most prolific source of Pliocene

fossils in Africa, which provides a unique picture of the south western Cape between about
5,5 and 4 mya. All of the mammal species, and many of the genera are extinct. Many are

known from this locality only, and this has filled many gaps in our knowledge of the Pliocene
fauna of Africa as a whole. The information detailed below can be found in the popular

booklet by Q. Brett Hendey of the South African Museum, who spent over 20 years studying

the site. (Hendey 1982.)

These estuarine sediments were laid down when the sea-level was rising in response to a

phase of extensive melting of the Antarctic ice cap. The coast was between 45 and 60 m
above the present, some 10 km inland and the granite high points at Vredenburg-Saldanha,

Postberg, and at Yzerfontein formed a series of sheltering islands. An extensive sandbar
closed the estuary of a more southerly precursor of the Berg River. (Fig. 1.1.)

Abundant marine shells indicate that the sea temperatures had cooled to much the same as

those of the present. While the fauna included species that lived near the river, the occurrence

of species adapted to more open habitats shows that the vegetation differed from that of the
Miocene. Forests and woodlands were now limited to the banks of the river while the

surrounding countryside was more open with grasslands and many of the Fynbos vegetation
types that are characteristic today. (Fig.1.2.)

As sea level rose even higher, the sand bar was drowned. River sediments discharged into the

sea, covered the earlier estuary and preserved the bones of animals that had lived and died

along its banks. River channel deposits in these sediments indicate the river’s northward shift
towards its present position. The channels are rich in fossils of animals that were washed

down from habitats further upstream by floods. The animals of this time also reflect the

continued deterioration of the environment to a cooler, more temperate climate than the
tropical conditions of the Miocene. Teeth of short-necked giraffes showing signs of dietary