Although important artifacts unearthed from prehistoric sites are moved, catalogued and preserved, most archaeological sites including dwelling foundations, surrounding sediments and shell heaps have been exposed to natural erosion. To protect the excavated prehistoric sites for further research, the writer and Mr. Sakurai of the Tokyo University invented new scientific methods for the preservation of Hamamatsu Corbicula Shell Mound, Shizuoka Prefecture, Japan. The mound is composed of approximately 30 square meters of shells, several dwelling foundations and human bones. Two archaeologists succeeded in preserving the entire mound by using mixtures of acrylic emulsion and water. They poured and injected the mixtures into well dried strata and dwelling foundations ensuring that the entire deposit of the mound would remain intact. The wrtier claims preservation of such a large area by using acrylic emulsion in an unprecedented event in the world.