THE ORIGIN OF TRON AND MANGANESE ORK 
IN BOGS AND STREAMS. 
By W. D. FRancis.* 
( Read hefore the Royal Society of Queensland, 1st May, 1916.) 
A. D. Hall} in writing on the origin of iron ore in 
undrained soils has stated that further investigation is 
required regarding the respective shares of the iron bacteria 
of Winogradsky, on the one hand, and the purely chemical 
actions of solution and reduction by organic matter and 
carbonic acid followed by redeposition on evaporation, on 
the other, in its formation. 
Ehrenberg showed that bog iron ore investigated by — 
him consisted of the remains of alge.{ Although it can 
be shown that his observations are not universally applic- 
able, it is interesting to notice that Ehrenberg ascribed 
the origin of the ore to organic agencies. Investigations 
by the writer show that ferruginous and manganiferous 
material in bogs and streams at Kin Kin, which is a stage 
in ore formation, is composed very extensively, if not 
entirely, of micro-organic material, chiefly bacterial. A 
few alge, and less frequently protozoa, are also present. 
Besides numerous cocci and bacilli, long filaments are abund- 
ant, which in many cases composed the greater part of the 
* The author in a separate paper records the observation, in the Kin 
Kin district, of (1) the presence of a red algoid plant on rocks in streams 
in scrub country ; and (2) the occurrence of a black manganiferous incrusta- 
tion in similar positions in cleared country. He considers that the black 
manganiferous incrustations result in some way from the death and decay, 
or replacement of the red algoid plant.—EKd. 
+ A. D. Hall, ‘ The Soil,” 1912, p. 286. 
{ “‘ Student’s Lyell,” 2nd Edn., 1911, pp. 48-49. 
