The deposits studied by the author are crusts and coatings of manganese oxide (mixed psilomelane, wad and limonite) on a consolidated marl. They were recovered from the lake bottom at two points approximately 2 km apart and at a depth of about 18 to 22 m. The lake is deeper than a typical bog swamp and its bottom is a soft blueish and clayey marl. Some of its banks are occupied by moorlands. The occurence of manganese concretions seems to be limited to a few small perimeters. The author analysed both the rind and the carbonate core of one of these concretions (NOTE: The Austrian lake anciently called Zellersee zum Mondsee is now known as Irrsee).

Samples have been air-dried before analysis.From 1983 until 1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions. At the time it was the most extended data compilation on ferromanganese deposits world wide. Initially published in a proprietary format incompatible with present day standards it was jointly decided by AWI and NOAA to transcribe this legacy data into PANGAEA. This transfer is augmented by a careful checking of the original sources when available and the encoding of ancillary information (sample description, method of analysis..) not present in the NOAA-MMS database.

Supplement to: Lasch, H (1930): Über Manganerz-Konkretionen vom Zellersee bei Mondsee = on the manganese concretions from lake Zellersee bei Mondsee. Zeitschrift für Kristallographie, Mineralogie und Petrographie, Tschermaks mineralogische und petrographische Mitteilungen, 40(3-4), 294-297