In 2012,  Gregory Harpel, an amateur paleontologist digging around a streambed in Monmouth County, N.J., stumbled upon what he first assumed to be a rock. It turned out that it was the other half of a humerus belonging to a sea turtle that existed 70 to 75 million years ago. The discovery had another surprise: the other half of the humerus was already in the possession of Drexel University, which acquired it around 160 years ago.

The sea turtle existed in the Cretaceous Period, and was about 10 feet tall, making it one of the largest sea turtles that ever existed, according to the Christian Science Monitor. Scientists believe it resembled modern loggerhead turtles. Watch the video from Drexel University to see the two halves of the humerus bone finally come together.