Caves in Mt. St. Peter; Maastricht. View of the interior gallery; and men excavating a fossil head of a crocodile-like mosasaur; Mosasaurus hoffmani. Handcoloured copperplate engraving from Bertuch's 鈥楤ilderbuch fur Kinder' (Picture Book for Children); Weimar; 1798. Friedrich Johann Bertuch (1747-1822) was a German publisher and man of arts most famous for his 12-volume encyclopedia for children illustrated with 1;200 engraved plates on natural history; science; costume; mythology; etc.; published from 1790-1830.