Chris T wrote:er...looking at the picture again what you have there is a portable bellows: I would assume the actual hearth is a pile of turf.
Sorry to be a pain!
I agree the forge looks quite substantial. In fact looking at the picture they have built two house like structures so building a forge would not be that tricky. Whether the bellows were brought from England to use in such a situation or fabricated on site is not something I know either? Having read a few accounts of early settlers/explorers they were a pretty resourceful lot who would knock things up if the need arose. For example, The Popham colony in Maine in a year 1607:
"... built a storehouse, other buildings including a house for Raleigh Gilbert. They explored, got food from the Natives, fished, searched for gold. They also built a 30 ton boat called a pinnace. This was the Virginia built under their shipwright Mr. Digby." from http://shallopproject.org/Shallop_Project/History.html
Not bad going so perhaps the forge in the picture is a more accurately termed a 'temporary forge'?
I'll stop rambling now