Between
Ngorongoro Crater and Serengeti plains lies the narrow fifty kilometre
long (31 mile) strip of the legendary Olduvai Gorge - where some of
the most important fossil humanoid remains have been unearthed.
The
gorge has been a surprisingly productive site for archaeological excavations
due to a number of important factors.
Millions
of years ago the area was abundantly inhabited by many species of
animal.
Finds
have shown these to include a sabre toothed big cat, a horned giant
giraffe, two kinds of elephant and various predecessors of today's
plains game and of course, early man.
Together,
all their remains were preserved in the alkaline mud of the lake that
once covered the area.
Over
the centuries these were fossilized and only exposed recently when
a seasonal river cut through the ancient beds.
It
was here that the Leakeys discovered the partial skull of the now
famous Zinjanthropus, who lived some 175 million years ago.
In
places, the gorge rises up 60 metres (197 feet) and the layers of
sediment deposited in the ancient lake can be seen clearly.
The
bones and teeth of over 150 species of animal have been excavated
from the gorge's rich stretch and an almost continuous record of human
habitation has been recreated from excavated artifacts, from the earliest
tool users to the Stone Age.
