The Ngorora sedimentary sequence is the only major fossiliferous unit between 9 and 12 million years in sub-Saharan Africa that has been mapped and studied in detail. Consequently many of the taxa from it are new. Much of the fauna resembles material in the Siwaliks of the Indian subcontinent and the widespread ‘Tethyan’ faunas of southern Europe. It appears that there was a widespread homogeneous faunal province during the middle Miocene which may be viewed as an expanded ‘proto-Ethiopian’ zoogeographic region. During the mid-Miocene the ancestral Palaearctic zoogeographic region appears to have had a more northerly limit than that of the present day.
In addition, the sediments at Ngorora contain a variety of evidence contributing to an understanding of local and regional palaeoenvironments, tectonic and volcanic histories and sedimentology in a Rift Valley setting. During the period of deposition the Ngorora area seems to have been as varied as the Baringo/Hannington area at the present day. Habitats ranged from lacustrine, through fluviatile, gallery forest, open woodland and possibly grassland. The climate may have been seasonal, with wet and dry periods. It was probably never arid, but may have approached semi-aridity from time to time.
The occurrence of other sedimentary units above and below the Ngorora Formation enhances its usefulness in correlation. Comparisons can be made through time; changes can be observed in the faunas of the Baringo succession; and a picture is emerging of gradual faunal change as the result of local evolution plus migration from other areas. Earlier ideas
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