specimen discovieres in Alberta and Montana. The first remains of
Maiasaura have been found south of Choteau, visible on the map. For years until the 1960s and 1970s, anyone who has traveled through the area south of
Choteau, Montana might have come across
Maiasaura remains, whether such remains have been or have not been attributed to a dinosaurian origin. The first people who are confirmed as having found
Maiasaura remains laying on the "Egg Mountain" area (as it is called today), are two homestead families of
Bynum, Montana: the Brandvolds and the Trexlers. Marion Kathryn Brandvold (1912–2014, née Nehring), had inherited the "rock shop", Trex Agate Shop, that had been founded in 1937 by her first husband, Clifford "Trex" Trexler (1908–1962). In the years that preceded 1978, she and her second husband, John Brandvold (1937–2020), had been finding small bones and they had been trying to put them together. But in 1978 paleontologists
Bob Makela and
Jack Horner arrived at the shop in Bynum. Not having found interesting fossils to them, they were about to leave, then Marion Brandvold told them that she had something else. Still at the shop, she showed them two tiny bones that Horner identified as baby hadrosaur bones. They followed her to the Brandvolds' house, where she'd been keeping the remains of at least four individuals in a coffee can. This made Makela and Horner go to the site where these remains were apparently abundant (South of
Choteau, Montana), and they discovered nests and juveniles of a till-then unknown species of hadrosaur. The next year in July 1979, during the second summer dig, a lady student named Fran Tannenbaum, under the direction of Jack Horner, discovered the first whole dinosaur egg ever found in North America and in the Western Hemisphere. The same year, in 1979, Makela and Horner
described and named the
type species Maiasaura peeblesorum. With time the site of this discovery earned the name "Egg Mountain", because of the abundance of hadrosaur eggs and eggshell pieces found in it. A skull of
Maiasaura, specimen PU 22405 (now in the collections of the Yale Peabody Museum of Natural History as YPM PU 22405 following the transfer of the Princeton University vertebrate paleontology collections), was discovered by
David Trexler's wife Laurie Trexler in 1979. It is the specimen that paleontologists Jack Horner and Robert Makela had used the same year as the
holotype of the new species. The
specific name honours the families of John and James Peebles, on whose land the finds were made.
David Trexler, the second son of Clifford Trexler and Marion Brandvold, grew up in such a context that he ended up by becoming a paleontologist himself. In 1995 he founded in Bynum the
Montana Dinosaur Center. That center plays an important role in connexion with the first identified remains of
Maiasaura because during the years that spanned from 1998 to 2004, David Trexler's mother Marion Brandvold led a legal fight with the Yale and Princeton universities in order to recover the bones of the baby
Maiasauras that she had found back in the 1970s. In 2004 she obtained a satisfactory issue and, since then, these historically important fossils are preserved at the Montana Dinosaur Center in Bynum. Over 200 specimens, in all age ranges, have been found. In 1985
The Nature Conservancy purchased the site of Egg Mountain from the James and Marian Peebles family, the original owners of the land, leasing the property to the Peebles for cattle grazing and allowing curator Jack Horner and the
Museum of the Rockies to run a paleontology field camp. In 2004, the Museum of the Rockies purchased the property and now the Museum gives "Egg Mountain" the name of "Museum of the Rockies' Beatrice R. Taylor Paleontology Research Site", honouring Beatrice Taylor, whose family donated the money for the purchase. ==Classification==