This number consists of a series of about one hundred and ten short biographies of 17th, 18th, and 19th century people who have contributed to the geology of the Netherlands, Dutch as well as foreigners. It does not pretend to be a critical survey but it will be informative for the general reader. The background of the present work is formed by the bibliographies of the geology of the Netherlands by JONKER (1907) and STEENHUIS (1934). Although no completeness has been pursued, it is thought that at least all main contributors in this field before 1900 have been inserted. A regional survey of names is given on p. 56, an explanation of the plates on pp. 57-58, and a register of names on pp. 59-60. A regional survey of names is given on p .76, an explanation of the plates on pp. 77-78, and a register of names on pp. 79-80.