On Wednesday, the skulls were sent to the Utah State Division of History in Salt Lake City, where State Archaeologist Kevin Jones examined them and determined they came from an adult and a child. He believes they are either Fremont or Anasazi, cultures that disappeared from Utah in the 13th century.
"That's all we know right now," Jones said. "We will look at them in more detail, take some measurements and kind of determine as much as we can about them their general health, if we can tell anything about cause of death."
At some point, he said, his findings will be reported to the Native American Review Committee, which could recommend repatriating the remains to a specific tribe. Jones said it is unlikely his office can affiliate the skulls with a particular modern tribe. His said his office has a year to complete the analysis.
Such deliveries of human remains to academic institutions aren't unusual. Last year, BYU received a skull in the wake of a controversial federal investigation into illegal trafficking of American Indian artifacts in Blanding.
"Oftentimes, somebody found bones in the garage after Grandpa passed away and they know something should be done about it, so they stick them in the mail without a return address," Jones said.
While the public may presume that people at universities know what to do with old bones, an unexplained delivery raises many questions that authorities are obliged to investigate.
Augusta is a ranching town in western Montana west of Great Falls, but Montana 3 doesn't pass near it. At this point, the origin of the skulls remains a mystery, and Utah has enlisted the help of the local Montana sheriff to track down the return address, Lemmon said.
So far, authorities don't know what prompted "Jim Crow" to mail the skulls.
"I have no idea of intent, or if that's an actual person," Lemmon said.