Letting Go

I have gathered shells
From many shores,
Fractured valves
Impressed by the flesh
Of former inhabitants.
And I have scrambled as a child
To snatch a darling cockle
Tumbling in the receding tide.
But now that I am older,
I mourn less the loss
Of these things.
I know the ones
Swept away
Belong to the sea
And not to me.