Anachronisms in the Book of Mormon 1000 years before the Jaredite record in the Book of Mormon begins. The main point of contention is how late these animals were present in the Americas before becoming extinct. Various Mormon authors have cited evidence that North American mound-builder cultures were familiar with the elephant. The oldest mound-builder societies date to around 2000 BC. The mound builder/elephant controversy did not originate with the Book of Mormon. In "The Mound Builders, Their Works and Relics", author Stephen Dennison Peet cites instances of exhumed mastodon remains and arguments given for why the remains were believed to be contemporary with mound builders.
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