This is a set of hand forged, iron ice creepers. They would be tied just in front of the heel of a shoe, and make it easier to walk on densely packed snow, or ice. They measure around 1.5″ x 2″ x 4.25″. For source and more details, click here.
Here is another example:
Image from: http://www.cr.nps.gov/museum/exhibits/revwar/image_gal/morrimg/creepersmorr.html, http://www.nps.gov/history/museum/exhibits/revwar/image_gal/vafoimg/frameshell.html