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'Thomas Ryder, Founderer, Scotland Bridge' is listed in the 1772 directory for Manchester and Salford. There are only three foundries listed in the directory, and the other two entries (Samuel Bagshaw and John Burrow) are referred to as brass founders, so it seems reasonable to suppose that Ryder's was an iron foundry. This assumption would be consistent with his connection with Marston Forge.
Scotland Bridge crossed the River Irk, linking Salford and Manchester, just east of the present Manchester Victoria station.