A cache at a roadside geological marker just south of Choteau.
Egg Mountain is the name given to the area where the first fossilized dinosaur nests were found by well-known palentologist Jack Horner -- a find that changed everything we thought we knew about dinosaur behavior.
Marion Brandvold, owner of the Trex Agate Shop (aka The Rock Shop) in Bynum, discovered the remains of juvenile dinosaurs in 1977, which she showed to Horner in 1978. Horner and his team began excavation of the area which led to the discovery of the nesting sites in 1979. The fossils belong to the dinosaur Maiasaur peeblesorum, the "good mother dinosaur" -- named for the nesting behavior discovered at Egg Mountain. The Maiasaur was later named the Montana State Fossil.
This cache was placed just off the parking area. The terrain immediately below the cache gets quite steep -- I slid a bit while placing this, so I wouldn't recommend this for younger children, but the terrain is rather mellow to, from, and directly at the cache. This would be difficult to find in the winter if there is very much snow.
More information on Egg Mountain can be found on signs at this roadside stop, at the museum in Choteau, the Two Medicine Dinosaur Center in Bynum (www.tmdinosaurcenter.org), or the Museum of the Rockies in Bozeman (www.museumoftherockies.org).