I will describe this as carefully as I can. You find yourselves in a round chamber that is also a ledge over an uncertainly deep drop. Somewhere below, you can hear the sound of water falling; it is not a roar, but it is a good deal more than a trickle.
The "hole," which is the top of a limestone cavern, depicted in black. The walls surrounding the chamber, as well as the sheer wall on the other side of the hole, are depicted in grey.
The floor of the room has been made of stone bricks, shaped together and without mortar. The floor is almost perfectly flat. The walls are rough hewn out of the stone.
Near the lip, which simply drops away, there is a cage, about four feet wide. The cage has a ring on its top. Above the cage, and above the hole, you can clearly see a stone cylinder that has been carved into the ceiling, grooved in the middle. Prodding the cylinder with a stick will show that it turns on axis that have also been carved into the rock. You have no idea how this was done.
On the wall is a similar stone wheel, also seemingly carved out of the rock. This also turns, and quite easily. The interior stone must be naturally greasy, or incomprehensibly smooth. The wheel is toothed. There is a crude metal block that has been fixed as stop to disallow the wheel from turning one direction or - if the stop is lifted over the stone peg that holds it in place - the other. Apparently, the wheel can be used to haul the cage up or lower the cage. The cylinder in the ceiling would work as a windlass. The cage would drop down through hex 0205.
There is no chain anywhere in sight.