And the plot thickens regarding a distinct boundary between the wrought iron and "mild steel" alternees.
From METL's metallurgical study:

"The microstructure was banded, but there were not clear iron and steel microstructures. The overall material appeared to be a single piece of metal with segregations of inclusions. It is likely that the manufacturing process had combined the two original iron and steel materials into a more homogenous structure, but that without melting the combination was restricted to mechanical mixing and possibly diffusion.
The banded regions are likely predominantly comprised of the original chemical compositions, but during manufacture experienced changes."

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