Nilsonia yukonensis
Cycad
Late Cretaceous (Maastrichtian)
Hell Creek Formation
Wibaux County, Montana, USA

26mm cycad seed.

Nilsonia is an extinct genus of cycad or cycad-like plant that lived across the whole duration of the Mesozoic Era.  Its remains have been found in various parts of the world (Asia, Europe, Australia, and the Americas).