Clarkforkian
Considered to be within the Paleocene , more specifically the Late Paleocene , the Clarkforkian shares its upper boundary with the Thanetian . 
<triplet> Paleocene <subj> Late Paleocene <obj> has part <subj> Thanetian <obj> has part <triplet> Late Paleocene <subj> Paleocene <obj> part of <triplet> Thanetian <subj> Paleocene <obj> part of