Organ Fingering Notation

[zvm]

Hi All - New to the list but have used lilypond for years.  I have been 
setting some baroque organ works for some of my students.  There is a 
fingering symbol that I don't know the name of (and so it is hard to look up 
in the documentation without a name) ... I'm hoping that if I describe it, 
someone in the musical typesetting world will know its name and can point me 
to how to recreate it in lilypond ...

If I want the alto voice on the treble staff played with the left hand there 
is a symbol that looks like [ without the bottom line and if I want the note 
on the bass clef played with the right hand its a [ without the upper line 
...

Anyone know what I'm "talking" about?

Thanks

Zack