Surface of area just above base [see diagram, pi. 2, no. 4], showing 

 greatly dilated cortex, seamed, and marked by very distant and 

 oblique though irregular rows of leaf cushions (P), the indi- 

 vidual cushions being very close, serially, in each row. The 

 irregularly rhomboidal depressions between the leaf cushion rows 

 are characteristic of the lower % part of old trunks of Sigillaria 

 and Lepidodendron. 



