In the terrace area in Hoa An district, a monument of prehistoric man was discovered (December 2010) distributing in the high ground of Bo Ma village, Hung Dao commune . Here on the avalanche talus and hill slopes which were originally the ancient alluvial layers of terrace level II of Bang Giang River exposed a stratigraphic section containing archaeological relics, mainly flaking and chipping tools interbedded in conglomerate sheets, under a nearly 1m thick layer.
The relics found include spearhead tools (3 units), rudimentary chopping tools with horizontal mounting blade edges (14 products), vertical edge tool (1 artifact), and tool with 2 adjacent edges (2 artifacts).
The tools are made from river pebbles taken from Bang Giang River. Processing techniques are still rudimentary; tools have primitive shapes and grinding technique has not yet appeared. They have featured nuances of the Paleolithic period. Morphological as well as functional analysis of the tool set shows gathering played a particularly important part in the method of finding food sources of primitive people living here. They are spike hand hoes, rudimentary scraping, chopping and hitting tools used for everyday living activities. Based on the processing level as well as the types of tools, we can see that the relics found at this site are preparations of prehistoric people living in the Paleolithic period. On the other hand, the majority of the terrace level II in the north of our country dated back to the late Pleistocene period. From the above analysis, archaeologists have identified Bo Ma as a monument of primitive man living in the late Paleolithic period.
Working tools of prehistoric man found in Bo Ma village a) Relic of a dark grey – sharp blade tool (13.2cm long, 8.21cm wide, 6.6cm thick); b) Relic of a light grey oblique edge tool (11.55cm long, 13.31cm wide, 5.7cm thick) – a tool of prehistoric man discovered in the ancient terrace (level II) of Bang Giang River (Source: Cao Bang Museum)
Comments: Cao Bang Paleolithic inhabitants with low survival skills had to struggle with the nature, wild beasts and diseases to survive and develop. They chose to reside on two different types of terrain with different conditions: hill, river terrace terrain (Thuong Ha, Bo Ma) and limestone mountain, cave, stone roof terrain (Lung O).
Studies on the residence features of primitive inhabitants in the Paleolithic period in Cao Bang showed that they used to live near large rivers and streams or their tributaries. This proves that water played a very important role in the life of prehistoric man, especially the primitive man in Archaeozoic era. Although no remains of prehistoric human have been discovered in Cao Bang, their tools, the stones processed rudimentarily to form tools to make their living, were detected with a relatively large number in Thuong Ha, Lung O and Bo Ma. They are the proofs of residence and work of primitive people in Cao Bang.