In the United States, the fossilized remains of the mighty creatures that lived in eons past are subject to an age-old law—”finders keepers.” In America, if you find a dinosaur in your backyard, that is now your dinosaur. You can mount it on the wall, you can give it to a museum, or, as is the case with two notable dinosaur fossils, you can put them up for auction—garnering, if you’re lucky, millions of dollars in the process.

Montana’s Hell Creek formation is one of the premiere dinosaur-hunting grounds in the United States, and though much of the dino-laden land is secured as federal or state property, not all of it is. And that, says the New York Times, is the key: “unlike many countries that carefully control dinosaur fossils found on public and private lands, the United States restricts the collecting of fossils only on public lands. Fossils found on private land… belong to the landowner.”

Two fossilized dinosaurs were discovered on a private ranch in the Hell Creek formation a few years ago, their skeletons locked in what seems to have been a deadly battle. The fossils date to the Cretaceous, says the Times, the last major era of the dinosaurs, and they seem to be the preserved skeletons of two previously unknown species, “a Nanotyrannus lancensis, a type of pygmy T. rex, and a Chasmosaurine ceratopsian, a close relation of the Triceratops.”

Teeth from the predator were embedded in the neck and back of the plant eater, he said, while the tyrannosaur’s chest and skull were crushed as though the ceratopsian had delivered a kick from the side. The fossils provide potential evidence for two new kinds of dinosaurs, Mr. Larson said. They could settle long-running scientific debates over whether the pygmy tyrannosaur existed as a separate genus or was simply a juvenile T. rex, and whether it hunted as well as scavenged.

Because of the dinosaurs’ apparently unique deaths and potential novelty, scientists really want to get their hands on the fossils. But, because of the laws of the land, the dinosaurs’ discoverers are opting to sell them at auction. The sellers had offered the fossils to museums, like the Smithsonian or the American Museum of Natural History in New York, but the Times says the museums backed away because of the high price.

America’s laws around dinosaur discoveries have contributed to an ongoing debate over the global dinosaur fossil trade, with people asking what is the proper place for such important relics. On the one hand, scientists want to pull whatever information they can from these rare finds. On the other, it’s your land.

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Mongolia Is Turning Politicians’ Offices Into a Dinosaur Museum