Paleontological and Paleobotanical Museum (Nostimo) teeth of a shark that was 20–25 m long, and a Late Pliocene (3.5 million years old) tooth of an "Anancus arvenensis", a mastodon, an ancient relative of the elephant, which has been recognised here for the first time in the wider area of Western Macedonia. The mastodon which lived in this area was about the same size as a modern elephant, but with longer tusks. Also displayed are some Neolithic tools (from the 4th millennium BC): a fishing weight, and a blade for harvesting crops. Paleontological and Paleobotanical Museum (Nostimo) The Paleontological and Paleobotanical Museum () at Nostimo is
Extinct radionuclide long half-lives. A partial list of radionuclides not found on Earth, but for which decay products are present: Notable isotopes with shorter lives still being produced on Earth include: Radioisotopes with half-lives shorter than one million years are also produced: for example, carbon-14 by cosmic ray production in the atmosphere (half-life 5730 years). Extinct radionuclide An extinct radionuclide is a radionuclide that was formed by nucleosynthesis before the formation of the Solar System, about 4.6 billion years ago, and incorporated into it, but has since decayed to virtually zero abundance, due to having a half-life shorter than about 100 million