Lopez de Bertodano Formation
The strata date from the end of the Late Cretaceous ( upper-lower Maastrichtian stage ) to the Danian stage of the lower Paleocene , from about 70 to 65 . 5 million years ago , straddling the Cretaceous-Paleogene boundary . 
<triplet> Late Cretaceous <subj> Maastrichtian <obj> has part <triplet> Maastrichtian <subj> Late Cretaceous <obj> part of <triplet> Danian <subj> Paleocene <obj> part of <triplet> Paleocene <subj> Danian <obj> has part