a stoup

This was taken by a church entrance and I think this is what the bowl is called. It should normally contain holy water - you dip your fingers in it and make the sign of the cross.

Why though the carved image of a skull? Intimations of mortality (to misquote Wordsworth)?

Maybe it's a reminder that we are all supposed to have some sort of life after death, through the resurrection of Christ.

One short sleep past, we wake eternally,
And death shall be no more; Death, thou shalt die. (John Donne)