[T]he Pebles, Pyritæ, Amber, or other like Nodules, vvhich happened to be repoſed in thoſe Cliffs, amongſt the Earth ſo beaten dovvn, being hard, and not ſo diſſoluble, and likevviſe more bulky and ponderous, are left behind upon the Shores, being impeded, and ſecured, by that their bulk and vveight, from being born along vvith the Terreſtrial Matter into the Sea.
Source: wiktionary