| Sloanzilla |
"The transmuted creatures can tread on any liquid as if it were firm ground. Mud, oil, snow, quicksand, running water, ice, and even lava can be traversed easily, since the subjects' feet hover an inch or two above the surface. Creatures crossing molten lava still take damage from the heat because they are near it. The subjects can walk, run, charge, or otherwise move across the surface as if it were normal ground."
The description "you hover an inch above the ground" technically makes it sound like you could walk across chasms or canyons, but I'm sure that's against RAI.
However, I'm assuming someone with a ring of water walking is immune to the ground applicatio of the grease spell, since his or her feet are not touching the ground?