In November 1924, a fossilized child's skull was found in a quarry at Taung in the present-day Northwest Province. Professor Raymond Dart discovered that it had several features that were more human than ape-like: the face was flatter, the head rounder and the brain larger. Most significantly, in the Taung Child the foramen magnum – the hole in the skull through which the spinal cord passes – was towards the front of the skull, indicating that this creature stood on two legs. In a four-legged creature, the foramen magnum is further back.
Dart classified the specimen as Australopithecus africanus (man-ape of southern Africa). But the scientific establishment was very critical because of its prejudiced belief that humans originated in Europe. The discovery in England of Piltdown Man in 1912 supported this view – until it was revealed to be a hoax.
In 1936 and 1947, more Australopithecus fossils were found, proving Dart right: early humans did originate in Africa about 2-3 million years ago.
Links:
http://www.modernhumanorigins.com/taung.html