34 
EDWARD S. SIMPSON, B.E., F.C.S. : 
known as a petrifying agent, roundish lumps of this material containing 
well preserved and determinable woods are found, according to Vater, 
in abundance in beds of phosphorite in Brunswick. Portions of the 
wood of Catamites preserved in this phosphate, according to Stur, are 
found also in the uppermost beds of the Coal-measures. Grand 'Eury 
reports the presence of similar fossils in the " couche des Rochettes 
and the ‘ couche des Littes.’ . . Barytes, pyrites, red and brown 
iron ore, argentiferous copper glance and argillaceous earth are also 
said by various authors to be petrifying agents.” 
Laubach also speaks at length of the well preserved 
fragments of wood, etc., converted into coal. 
Other writers refer to the occasional occurrence of 
phosphatised wood in conjunction with “ coprolite ’’ beds. 
Thus D.C. Davies j- mentions its appearance in the Cretaceous 
phosphatic deposits of the Ardennes and Meuse stretching 
across the frontier of France and Belgium, and also in the 
similar beds of the Russian provinces of Smolensk, Orel, 
Komsk and Voronife. Prof. R. ZeillerJ says : — 
'•It is not uncommon to find vegetable remains, especially frag- 
ments of stems, whose tissue has been completely mineralised by the 
action undoubtedly of waters feebly charged with silica, carbonate of 
lime, carbonate of iron, or sometimes even phosphate of lime.” 
Every authority speaks of the comparative rarity of 
phosphatised wood, and speaks very indefinitely of the actual 
mineral species present. It is not certain, therefore, whether 
previous cases were known of the conversion of wood into 
genuine fluor-apatite, containing theoretically 7.7 per cent, 
of calcium fluoride and 92.3 per cent, of calcium phosphate, 
or whether these cases were instances of conversion into 
“ phosphorite ” containing little or no fluorine. The con- 
version of wood into dufrenite does not seem to have been 
observed elsewhere. 
The phosphatic beds at Dandarragan, from which these 
specimens came, have been superficially examined by one 
of our members, Mr. W. D. Campbell, and described by him 
in Bulletin 26 of the Geological Survey of W.A. They con- 
sist of : — ■ 
(a) An upper bed of pale coloured sandstone 
carrying numerous concretions of calcium 
phosphate (coprolites) , with a little secondary 
dufrenite and wavellite, the whole rock 
averaging 15 to 20 per cent, of P* Os . 
(b) A lower bed of highly ferruginous sandstone, 
carrying dufrenite, with at itmes a little phos- 
phorite or vivianite. Assays showed 7 to 15 
per cent. IT O5 . 
t Davies, D.C. ” Earthy and other Minerals and Mining,” p. 1 54- 
+ Zeiller. R. Elements de Paleobotanique,” p. 9 . 
