Science

[Samblain]

What was ironstone used for ?

[Old_Geezer]

To extract iron from ?

http://en.wikipedia.org/wiki/Ironstone

BTW, informative title you have there.

[dundurn]

As OG suggests and the wiki entry confirms it was a commonly used iron ore. Near Bournemouth on Hengistbury Head there were significant deposits of ironstone. These were much depleted in the 19th century when a local firm landed a lot of Newcastle coal for its operations. The ships returned to Newcastle in ballast, not having a return cargo. The ironstone was used as a dense and importantly free way of loading down the ships. The stones had been an effective sea defence and the Head was much diminished as a result of their abstraction.