The group sets off down the tunnel in the skiff, Olmar propelling and others helping steer (which they need to do, Olmar's punting skills are minimal and the skiff has a tendency to zig-zag from one side of the tunnel to the other).
There is but one route that the underground river takes, sometimes through narrow channels where the passengers in the skiff can touch both walls, and where Olmar finds the pole sinks deep into the chill waters. Othertimes the tunnel widens out, and the shoals become so shallow that you have to get out of the skiff and portage it across to deeper water, but all the time moving onwards.
By the light of a burning brand taken from Kane's campfire, the tunnel emerges from the darkness in front of the skiff, and then vanishes again behind; you feel as if you are in a tiny bubble of light far beneath the earth. From time to time, the tunnel passes through worked archways with Ur-man glyphs inscribed upon them. Sometimes a particularly narrow section of tunnel shows signs that it has been worked to widen it enough for the skiff to pass through, but otherwise you find yourselves in natural rock.
Finally, as the brand is almost burnt through, you see a pale blue light illuminating the tunnel ahead, and then the skiff comes out into a huge cavern, on a lake so dark and still it looks like a black mirror, or a pit of emptiness.
On the far side of the lake, the river flows into two tunnels, neither of these bearing an Ur-man arch. In between these two tunnels is a broad shingle beach, and on the beach, partially carved into the wall of the cavern, is an ornate columned portico. Spaced around the shore of the beach are columns that echo those of the portico in style, but instead of supporting a pediment each one is topped by a blue flame that burns coldly and silently.
[sblock=Xoria]
The Ur-man glyphs don't seem to mean anything - perhaps just a method of labelling the archways to denote position along the river.
[/sblock]