Over 100 iron furnaces from the 3rd-4th century were located near Sudice (Czechoslovakia) 0.4-0.8 m below the soil surface by use of a proton magnetometer. Samples of iron found in the furnaces had a relatively high content of Si, Al, Mn, Ti, U, and Ra, and a low content of C, S, Pb, Zn, and Cu. Temperatures in the furnaces were above 96096 as determined by differential thermal analysis of the inside surface of the furnaces. -- AATA