Among the things you can expect from a leisurely bike ride with your 4-year-old son—fresh air, exercise, bonding—accidentally stumbling upon ancient human remains is not among them. Yet that’s exactly what happened to Matt Kiddle earlier this month near Port Angeles, Washington, when a spin around the area revealed a weathered skull erupting from the ground.

Kiddle was biking with his son, Ivan, along the Olympic Discovery Trail when the two came across the skull and mandible. The pair climbed off his bike and walked on to the beach for a closer look, where Kiddle also noticed a scapula, or shoulder blade. Later, another pedestrian noticed a hip bone.

Fearing they had stumbled upon a crime scene, Kiddle examined the remains and realized the bones were likely old. He called the police. A forensic archaeologist determined they’re between 500 and 1000 years old and are of Native-American origin.

"Frankly, my first reaction was, what poor individual is missing that I just found their bones, then I quickly realized they were very old and likely Native American, and some form of ancient individual," Kiddle, a physician assistant, told the Peninsula Daily News.

How did the remains manage to become visible? Parts of the Trail have crumbled due to coastal erosion, revealing below-surface discoveries like this one.

The Washington Department of Archaeological and Historic Preservation will now look to determine which tribe the deceased belonged to so the bones can be repatriated and properly laid to rest.

[h/t Smithsonian]