Stone-monuments, distributed in this area, have been investigated and studied on the characteristics and the rock phases in the geological and conservational points of view. Most of them may have been built from the end of the Shilla Kingdom to the Koryeo Kingdom, which are based on the typical characteristics of the form. The used rocks in these monuments are mainly biotite granite of the Jurassic age which is widely distributed around the area. Black slate and marbles are also used in some monuments, which may be obtained from other areas. The biotite granite of massive and coarse texture contains often inclusions of biotite aggregates or fragments of dioritic rock phase. However, the biotite granite in the area may be very weak to the chemical weathering so that irregular rock surface shows generally $2~3mm$ relief. The irregular relief is mainly due to different relative degree on the chemical weathering according to the kind of minerals especially quartz, feldspar and biotite. The chemical weathering is also influenced by organisms. For conservation, they must be scientifically considered based on the characteristics, kind of the rock phase, factors on the weathering process, situation in situ or being transported, and protection.