For such an apparently inoffensive lanscape feature, the Canyon of the Three Gates caused me untold difficulties. This was because it connects the internal world of the caldera of Osrakum with the outer world. As such it modulates the flow of water from the Skymere lake into the Gatemarsh. Added to the hydrological complexities were those of origin - the volcanic erruptions that brought the basalt columns of the Valley of the Gate into being. If this was not enough, there were the complexities of how the Chosen had drained the lake to expose the coombs for habitation.

The first two diagrams show cross-sections through the Canyon showing the many levels that needed to be calculated.

A is the Wheel. B is the point which the lava eruption from the cone at C reaches down the Canyon. It is at C, the highest point within the Canyon, that the Ichorian Gate is located.

The third diagram is shown upside down so that north is to the top.

The smaller sketches on the right show how ring fractures (concentric on the caldera) cause the right angle turns in the Canyon.

The main sketch shows the 'pomegranate' cone which erupted at one of these turns. This eruption poured basaltic lava both down the Canyon and into the Valley of the Gate where, on cooling, it produced the characteristic hexagonal columns.

The cone momentarily blocked the outflow from the lake which eventually eroded its way through by means of a waterfall.

The fourth diagram shows the pomegranate cone as it was in the Quyan period. At this time the lake reached up to here.

Employing vast numbers of sartlar, the Chosen cut the Cloaca into the floor of the Canyon so as to lower the level of the lake in Osrakum, thus exposing the floors of the coombs for habitation. (The various stages of this are listed on the expanded page.)

When making the Cloaca, a second channel was cut isolating the pomegranate cone upon which the Ichorian Gate was built.