They walked along the tributary for about a day.
It took a long time, but the journey wasn't far. They had to watch carefully as they walked, searching both sides of the river. They even needed two or three vehicles to search repeatedly, fearing they might miss something.
"Brother Ying, there's nothing here. We asked the locals, and they said there are several pits on this mountain, the deepest being about twenty or thirty meters. The leader wants us to hike up the mountain and check these pits."
The origins of the mountain pits are subject to debate. Some say they were formed by earthquakes, others by meteorite impacts, and some claim it was caused by mountain bandits digging tunnels which collapsed.
They contacted local geology experts, who sent them a map marking several hazardous pits.
