- The petroglyphs are a mystery, yet give us a glimpse into the lives of an ancient Native American people who once occupied Michigan's Thumb area.
- The spiral motif is found numerous times carved into the sandstone rock. There is no consensus of what the spiral represents.
- This cluster of different carvings shows a human figure in the center, a representation of a bird on the left, hand prints, and birds in flight.
- The Thunderbird is a common motif in many Native American societies, including those of the Great Lakes. It was a mythical bird that could create thunder, clouds and lightening, and control rainfall.
- The North fork of the Cass River flows through the property of the Sanilac Petroglyphs State Historic Park. This waterway first brought the Anishinaabe (Ojibwa) people to the area and evidence of campsites along the river has been found.