For three summers the Geological Survey of Norway has carried out a special hunt of pyrite boulders within the Grong area and adjacent districts. One result is the establishement of a marked boulder train from the Joma pyrite deposit to the coast, a distance of close to 90 km, see fig. 1. In all about 230 boulders have been found, most of which have been plotted on fig. 1.
Med mindre annet er angitt, så er denne innførselen lisensiert som Navngivelse 4.0 Internasjonal