The K–Pg extinction event, brought on by an asteroid impact (Chicxulub impact) and possibly volcanism (Deccan Traps), marked the beginning of the Paleocene and killed off 75% of species, most famously the non-avian dinosaurs.

citation

Wikipedia contributors. (2024, March 5). Paleocene. In Wikipedia, The Free Encyclopedia. Retrieved March 12, 2024, from https://en.wikipedia.org/w/index.php?title=Paleocene&oldid=1211962279

It is well known that a vital ingredient of success is not knowing that what you’re attempting can’t be done. Terry Pratchett, Equal Rites

Paleocene (Wikipedia) The Paleocene, (IPA: /ˈpæli.əsiːn, -i.oʊ-, ˈpeɪli-/ PAL-ee-ə-seen, -⁠ee-oh-, PAY-lee-) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek παλαιός palaiós meaning “old” and the Eocene Epoch (which succeeds the Paleocene), translating to “the old part of the Eocene”.