Seed circle mystery

I am in full swing sowing seeds, and a LOT of it is from our seed circle here.

I came across a packet this morning, one of those triangular ones that have been folded out of a piece of paper. The label has rubbed off onto something else, so I have no idea what they are.

So, join me in this mystery collaborative. The evidence are as following:
The seed packet was folded out of a gardeners world magazine.
The seeds are black beans with a little white dot on the belly.
Google searches come up with black beans/turtle beans.
Search on this forum doesn't bring up any seed circle posts that mention turtle or black beans.

I will hold off sowing them, as it's only just February.

The plot thickens.