Меловой период

Landman N.H., Kennedy W.J., Larson N.L. (2015) A New Species of Scaphitid Ammonite from The Lower Maastrichtian of the Western Interior of North America, with Close Affinities to Hoploscaphites constrictus Sowerby, 1817 // American Museum Novitates. Number 3833. P.1-40. doi: http://dx.doi.org/10.1206/3833.1

http://digitallibrary.amnh.org/dspace/b ... sequence=1