It was believed that during the earliest prehistoric periods, from the close of the fourth millennium BC, Hong Kong experienced a change in the environment, in which the sea levels rose from as much as 100 meters below the present level.
Ancient artifacts suggest a strong dependency on the sea.
According to recent excavations, archaeologists have discovered two main Neolithic cultures lying in stratified sequence. Pieces of coarse, cord-marked pottery has been found together with fine, soft, fragile pottery decorated with linear carvings, perforations and paintings. The fourth millennium BC is associated with this phase. In the next phase, probably in the mid-third millennium BC, a new ceramic form decorated with a wide range of impressive geometric patterns was found. Better workmanship and a melange of different shapes indicate a progression in techniques.