PLATE CLXXIX. 
INTERNAL STRUCTURE OF FosstL Woop FROM THE JURASSIC OF THE 
Buack Hiuus in Soura Daxora. 
Figs. 1-6. PrnoxyLon DACOTENSE Kn. gen. et sp. nov ...--------------------- 
Fig. 1. 
Fig. 2. 
Fig. 3. 
Transverse section, showing sharp line of demarcation between fall 
and spring wood. x 320. 
Transverse section of resin passage in fall wood. x 320. 
Radial section, showing medullary rays with irregularly thickened 
walls and small bordered pits. x 320. 
. Radial section, showing bordered pits on walls of spring wood. 
x 820. 
. Tangential section, showing a single medullary ray. x 320. 
. Radial section, showing manner in which the medullary rays are 
thickened and also the ends of the cells. x 320. 
Page. 
420 
