Dunagiri-Stones at Dunagiri Temple Rock symbols.
The rocks symbolise one or more of any of various deities, e.g., deity for well-being of livestock in areas where livestock is important. Such rocks are found in temples as well. In place of a statue or an idol, a rock is placed to symbolise the deity. Worshippers know an elaborately carved statue of a specific deity is also essentially a piece of rock - the difference between a mere rock and an idol being the devotion and faith in heart of the devotee. Amazing simplicity and clarity in thought. This must be one of the earliest use of symbols in religion.
By Dunagiri Retreat Piyush Kumar