Some of you may know me to be an avid dinosaur-egg collector. Sadly, most eggs these days come only from China or European countries. Recently, I was lucky enough to acquire a North American dinosaur egg - A Maiasaura peeblesorum egg from Browning, Montana.
This hatched egg dates to the late Cretaceous, and is inflated unlike other eggs from that area.
Maiasaura is the very picture of motherly dinosaurs and nesting behavior; this egg is thus one of my favorite fossils.