Er, which side? There are three sides you can leave the raft on: Lower, upper right by the chest, and upper left. There's at least one illusionary wall by the chest. (To its right, I believe.)then got the raft stuck on the dock where I first left and now can't use it.
I didn't get past it either. Would love some tips.I then made the sylph by the medallion thing visible, but it didn't help in me being able to get past it.
To get the key:Spoiler: show