Fossil Otodus Obliquus shark tooth embedded into rock matrix, 5-66 million BC.A tooth from a shark Otodus Obliquus, which lived from the Paleocene to the Miocene.Weight: 1 lb. = 450 g;Measurements of the rock: 4 x 4 x 1.5 inches;Height of the tooth: 2.5 in. = 64 mm;The Paleocene (pronunciation: /ˈpæliəˌsiːn, ˈpæ-, -lioʊ-/[2]) or Palaeocene, the "old recent", is a geologic epoch that lasted from about 66 to 56 million years ago. It is the first epoch of the Paleogene Period in the modern Cenozoic Era. As with many geologic periods, the strata that define the epoch's beginning and end are well identified, but the exact ages remain uncertain.The Miocene (pronunciation: /ˈmaɪəˌsiːn/[1][2]) is the first geological epoch of the Neogene Period and extends from about 23.03 to 5.333 million years ago (Ma). The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words μείων (meíōn, “less”) and καινός (cænós, “new”)[3] and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene Epoch and is followed by the Pliocene Epoch.