Photo of an incised New Zealand stone.

This is the Puniho stone found on a Taranaki Marae. According to a European farmer living nearby, the already incised stone was hauled out of the "Stoney River".
The same farmer says that there are many more with these strange markings on them at the bottom of the river.

The apparent design, in consideration of the severe weathering, appears to be very old and is hard to identify as a recognizable pictograph. It is also a significant departure from anything seen within recent eras of Maori culture. The ancient inhabitants (the Stone-people), when under siege from the Maori warriors, hid a lot of their most precious possessions in rivers or swamp/ wetlands...greenstone items...ornately carved panels, etc in the hope of being able to return and retrieve them later.