96 EXPLANATION OF PLATE 56 fl . 



Fig. 9. Vertical section of the dome-shaped trunk of Stig- 

 maria, showing the relative position of the branches. 

 (Lindley and Hutton.) 



Fig. 10. Restored portion of a branch of Stigmaria show- 

 ing the manner in which the long cylindrical leaves 

 proceeded from, the tubercles around its surface to 

 the length of many feet. In front, extending from 

 a. to b. is seen the depression adjacent to the internal 

 eccentric woody axis a. From b. to c. this axis is 

 laid bare by the removal of a portion of the sand- 

 stone. This part of the axis is drawn from a speci- 

 men in the Oxford Museum. Scale one-seventh. 

 (Original.) 



Fig. 11. Fragment of a branch of Stigmaria, showing the 

 character of the Tubercles, which formed articula- 

 tions with the bases of the leaves. The enlargement 

 of the leaf towards its base (a) seems to have been 

 calculated to strengthen this part, and to afford space 

 for the articulating socket. This socket formed, 

 with the spherical tubercle, a universal ball and 

 socket joint, admitting of motion in every direction 

 to a long cylindrical leaf floating in water. Scale 

 one-half. (Sternberg.) 



Plate 56 a . V. I. p. 363 et seq. 



Appearances presented by longitudinal and transverse 

 sections of recent and fossil Coniferous woods, cut into thin 

 slices, and magnified 400 times. (Nicol.) 



Fig. 1. Longitudinal Section of Pinus Strobus, cut paral- 

 lel to a medullary ray. 



Fig. 2. Transverse Section of the same. 



a. a. Portions of concentric annual layers. 



Fig. 3. Longitudinal Section of Araucaria Cunninghami. 



Fig. 4. Transverse Section of the same. 



