[Hugin]

"The iron was produced in the smaller side valleys, and transported to Forsetmoen for refining. From there iron artefacts have been transported to the larger farms further out. Maybe they've been sold even further," Rønne says.

Stands to reason. The first iron was made from black sand found along stream beds.

[SunkenCiv]

Thanks Hugin.

[Brugmansian]

Might have been bog iron. Wish these articles gave more information.

[gleeaikin]

In New Jersey, the early colonial iron manufacturing used “bog iron”. Clumps of sand and rust that had consolidated from the action of acidic waters caused by the local plants and trees.