Perflex EC-50 gasket -- which way is up?

[bakerfamily]

I'm in the middle of overhauling my perflex ec-50 filter. As I'm putting it back together I suddenly realize that I wasn't paying enough attention while taking it apart. I can't figure out which way the gasket goes. Here's a picture of a cross-section of the gasket:

What I can't figure out is whether the 'bump' goes up or down. Both ways fit nicely. Does anyone know?

Thanks for any help you can offer.

 

[Bama Rambler]

The bump should go up.

 

[bakerfamily]

Thanks! Up it shall be!