376 ERNEST WARREN. 



place of the woody substance bui-ns with a smoky flame 

 without obvious fusion. It is apparently quite insoluble in 

 alcoholj ether, benzole, carbon bisulphide, acids and alkalies. 

 The fossil wood colours a solution of potash deep brown, but 

 the jet-like mineral does not have this effect. 



This bituminous substance may probably be regarded as 

 consisting of one or more oxygenated hydrocarbons allied to 

 Bathvillite or Torbanite, but differing from them in 

 having a greater percentage of oxygen. 



The above description of the structural changes that the 

 wood undergoes in its transformation would constitute an 

 interesting introduction to the subject of the chemical 

 changes which lead to coal -formation ; and an exhaustive 

 investigation with the material at hand Avould undoubtedly 

 throw much light on the vexed question of the origin of the 

 different kinds of coal. 



The genus Eugenia is quoted by Schenk^ as occurring in 

 the Upper Cretaceous rocks of N. Greenland and Westphalia, 

 and it is therefore an ancient genus. 



The Water Boom is at present one of the dominant trees on 

 the coast, and there can be little doubt that the fossil wood 

 actually belongs to this species. 



The lignite bed of 2 ft. or more in thickness is chiefly 

 composed of the remains of this tree, and it occurs under a 

 thickness of some 60 ft. of soft sandstone. 



In number of years, therefore, the bed must be considered 

 as a very ancient deposit, although geologically it is probably 

 on the border line of Tertiary and Recent. 



The great contortion and the profound chemical changes 

 which have taken place in the wood also point to its antiquity ; 

 and it may be stated that the occurrence of this seam is 

 evidence of a great uniformity of climatic conditions and bio- 

 logical environment on the sea-board of East Africa for a 

 relatively very long ])eriod. 



' Zittel, Karl A.. ' Hauclbucli cler Pala;ontologie.' II. " Palseophyto- 

 logie," p. 641. 1890. 



