SPECIMENS OF FOSSIT; WOODS IN NATAL MUSEUM. 347 



The following definition of the genns Da doxy Ion End. 

 is given by E. A. Newell Arber.^ 



" Petrified wood of Palaeozoic age of the coniferous type 

 closely siinilar to that of the modern Araucaria\ Rings of 

 growth usually well-marked. Xylem centrifugally developed, 

 tracheides as a rule pitted only on the radial walls. P)ordered 

 pits, hexagonal in outline, usually contiguous, pluriseriate, 

 more rarely distant and uni- or biseriate. Pith usually large, 

 fistular or solid. Cortex as a rule without gum-canals or 

 resin-cells, but the latter are sometimes found in the cortex^ 

 wood and pith." 



Dadoxylon austral e Arher from Australia is described 

 as follows : 



" Pith not preserved. Xylem with well-marked rings of 

 growth, each as a rule between 3'5 and 8"5 mm. in radius. 

 Sometimes the growth is irregular . . . Tracheides in 

 transverse section, very small, narrow, square or slightly 

 oblong, with rounded angles, about twenty-five in a milli- 

 metre of length. Tracheides short, with hexagonal-bordered 

 pits only on the radial walls. Usually these pits are multi- 

 seriate and crowded, but not infrequently they are found to 

 be uni- or biseriate, distant or few. Medullary rays extremely 

 numerous, uniseriate, very rarely two cells thick, usually 6-12 

 or more cells in height. The medullary ray cells communicate 

 with the tracheides by 2-6 simple, oblique pits. Cortex 

 absent." 



I. DADOXYLON— FIRST SPECIES. 



(1) LIST OF SPECIMENS WITH LOCALITIES. 

 The specimens are arranged as far as possible in accord- 

 ance with their geological horizons. 



The following specimens of fossil woods in the Museum 

 apparently belong to the same species of conifer, and are not 

 clearly sepai'able from D. australe Arher. They are all 

 silicified, except when otherwise stated. 

 ' Loe. cit.. p. 190. 



