Ly Manh Thang, Deputy Director of the provincial museum said the relics are found in two layers. The below layer, which is almost 1m deep, contains working tools made from stones found in rivers and typical of the neolithic age.

The layer above, about 20 cm deep, holds more stone tools, as well as dozens of ceramic pieces. Animal teeth, bones and mollusc shells were found in both layers, which were traces of food left by prehistoric men.

The archeologists also found a tomb and seven stone tools inside.

Trinh Nang Chung, head of the Science Management Department under the Vietnam Institute of Archaeology said Nguom Hau cave was once home to many generations of prehistoric men, who lived here from 4,200 to 3,000 years ago.