Underground safe?

Hello, thank you for letting me join this awesome group! Im hoping to find some information on this piece. I have been online half the day trying to find "anything " about this cool thing! What I was told is that its airtight once closed and the cast iron, hinged lid has a spot to put a lock on it??? There are some markings on the bottom, but I cant read what is says :( it is terracotta with cobalt blue glaze on the outside and a white crackle on the inside. It stands just ove a foot tall.
Apparently they were used in times of unrest and people would bury their valuables in them. Underground, safes, or strong boxes. Anyway, I cannot find a single other online! Have any of you ever come across one? Thank you in advance for any info ????????