nreddleAn earthy variety of hematite iron ore. It is fine-grained, and sufficiently compact to be cut into strips, which are used for various purposes, as for marking sheep and drawing on board. This material is found in several localities in England, and much more rarely in the United States, where it is generally called red chalk.
nreddleA name applied by workmen to red-lead with oil when used to smear a surface which is being scraped to a fit.
Chambers's Twentieth Century Dictionary
nReddlered′l an impure peroxide of iron (ferric oxide) associated with very variable proportions of clay or chalk—also Red′-clay, Radd′le, Red′-chalk