(Tables, page 17-18), Chemical composition of ferromanganese concretions of the lakes of Northern Savolax in Eastern Finland

This paper discusses the occurrence of manganese-rich concretions in the lakes of Northern Savolax in Eastern Finland. The samples were collected in the summer of 1905 and left to dry for 2 months at room temperature. The quantity of H2O mentionned in the analysis was obtained by dessication at 155°C. The amount of Mn is calulated as MnO2 although other valences might be present in the samples. The contents in CO2 and organic substances was not determined. J. Aschan determined that as a general rule, in Finland the manganese rich lake deposits are rather associated with soft bottom sediments while the iron rich deposits are more assocaited with hard or sandy bottoms.

(Tables, page 17-18), Chemical composition of ferromanganese concretions in lake Storsjøen

This paper discusses the occurrence of manganese-rich concretions (Seeerz or see-erz, in german) in Storsjöen (46 km**2, 130 m above sea level) in southern Norway, (in the basement area, 70 km. Northeast of Oslo, then named Kristiania) and thereby contains a general discussion about the relationship between manganese and iron in the concretions as well as on the different precipitation of Mn-poor iron-manganese oxide concretions in the bottom of lakes from that manganese oxide rich concretions which are relatively Fe-poor.