A large boulder of rock which has been transported by a glacier so that it has come to rest on country rock of different lithology; all erratic blocks in northern Germany, for example, originated in Scandinavia (Bernhardi (1832) Jahrbuch für Mineralogie, Geognosie, und Petrefaktenkunde, 3). Agassiz (1840–1) Procs Geo. Soc. 3, 2 used the presence of erratics as evidence of glaciation in the British Isles.