The Jurassic/Cretaceous system boundary is an impasse. Why do not go back to Oppel’s 1865 original an historic definition of the Tithonian?
Journal: Cretaceous Research
Year: 2019

The lack of an absolute and persistent opinion regarding definition of the base of the Berriasian Stage, i.e., its instability over the past 50 years, casts grave doubts on its suitability to be the Jurassic/Cretaceous System boundary. The question "when does the Jurassic ends?" is addressed in a discussion on the highest Jurassic stage, the Tithonian of Oppel. The Berriasian of Coquand that came later was, amongst other options, considered either as Cretaceous and to be its lower stage, or as J