378 ERNEST WARREN. 



Fig. 9. — x 4U(>. Mus. No. 12. Small piece of longitiulinal section 

 of the same. The " fixed " decomposing walls of tracheides are seen 

 at r.tjAO. 



Fig. 10.— X 150. Mus. No. 232. Inyazan Junction. Zululand. 

 Transverse section of Eugenia wood. The tissue is fairly well silicified 

 as it contains over 70 per cent, silica. The preliminary changes (as the 

 filling np of the cavities of the wood filire with bituminous matter) for 

 the transformation into the jet-like substance had taken place and the 

 condition was then " fixed " by a considerable infiltration of silica. 



Fig. 11.— X 450. Mus. No. 232. Inyazan. Small piece of trans- 

 verse section showing an especially silicified wood fibre, d.f. The 

 cavities of the fibres are filled with l;>ituminous substance which is also 

 seen (i/,) between some of the fibres. At the bottom of the figure the 

 fibre walls have coalesced and the bituminous material has extriided out 

 into flake-like extensions. 



Fig. 12. — x 150. Mus. No. 232. Inyazan. Transverse section of 

 the next stage in transformation. The cells of the medullary rays and 

 most of the pitted vessels have become completely filled with the 

 bituminous matter. The outlines of the fibre walls have completely 

 disappeared. 



Fig. 13.— X 150. Mus. No. 233. St. Lucia. Zululand. Transverse 

 section of a later stage in the transformation. The bituminous masses 

 ai"e breaking down and becoming dispersed through the general matrix 

 (m.) which is itself being iiltered into a similar substance. 



Fig. 14.— X 150. Mus. No. 229. "Wood Bed,' False Bay. 

 Zululand. A still later stage in the transformation. The general 

 matrix is becoming more homogeneous ; but the course of the thicker 

 medullary rays is still oliservable (r.oi.r.) 



Fig. 15a.— X 100. Mus. No. 228. "Wood Bed," False Bay. A 

 transverse section of the jet- like substance exhibiting the remains of 

 the thicker medullaiy rays and a fairly homogeneous mati-ix with a faint, 

 very fine reticular structure. 



Fig. 15 b. — -x lOO. Mus. No. 228. Transverse section of similar 

 section viewed with crossed prisms. Running oblicpiely across there is 

 a system of dark and light bands. 



Fig. 16. — x 150. Mus. No. 232. Inyazan. Longitudinal tangen- 

 tial section of wood in the condition descrijjed under fig. 11. Pitted 

 vessels {p. v.). thylo.se (^//.). especially silicified fibres (d.f.) where most of 

 the lignified sulistance has been replaced, wood parenchyma ((t'.p.) and 

 pitted parenchymatous cells (j).c.) are shown. 



Fig. 17.— X 400. Mus. No. 234. Port Durnford, Zululand. Small 

 piece of longitudinal tangential section similar to fig. 16. The bitu- 



