In the archaeological record, a culture known as the Pan-Grave Culture is generally considered by experts to represent the Medjay. This culture is named for its distinctive circular graves, found throughout Lower Nubia and Upper Egypt, which date to the late Middle Kingdom and Second Intermediate Period (1800-1550 BCE). The sudden appearance of these graves in the Nile Valley suggests that they represent an immigrant population, while the presence of "Nerita" shells in many of them suggests their occupants came from the Eastern Desert between the Nile and the Red Sea. Other objects commonly found in these graves include the painted skulls of various horned animals, which are found either arranged in a circle around the burial pit or placed in separate offering pits.