I'm just looking over China Gates by John Adams. I can see in the first bar of the lower staff that the first note is played in the bass clef, subsequent notes are in the treble clef. This goes on through bar 15.
At bar 16, the mode is changed and it looks to me that the same idea is being followed: first note of bar 16 is in the bass clef because there's a bass clef in parenthesis before it, then (I think) the subsequent notes are in the treble clef because there's a treble clef in parenthesis before them.
I just want to be sure I've got this right. It's confusing because the notation of bar 1 and 16 could have been the same but isn't; the parentheses are used throughout the piece except for bar 1.