308 HISTORICAL GEOLOGY. 



2. Sigillarids. The family name is taken from the 

 type genus, Sigillaria. It includes Sigillaria and Sigil- 

 larialike plants. The name Sigillaria is taken from the 



FIG. 236. Lepidodendron FIG. 237. Sigillarids : Sigil- FIG. 238. Keetora- 

 modulatum. (After Les- laria reticulata. (After Les- tion of Sigillaria. 

 quereux.) quereux.) (By Dawson.) 



seallike markings (sigilla, a seal) left on the trunk by 

 the falling leaves (Fig. 237). They were the largest of 

 all the coal-trees. Boot, stem,, branches, and leaves have 

 been found. From these it is possible to reconstruct the 

 general appearance of the tree. Imagine, then, a tree 

 four or five feet in diameter at the base, with widely 

 spreading roots ; the trunk regularly fluted like a Corin- 

 thian column, and ornamented with vertical rows of seal- 

 like impressions (leaf -scars), and towering to the height 

 of one hundred to one hundred and fifty feet ; the top 

 branchless, or else with only a few large branches clothed 

 with grasslike or yuccalike leaves. The fruit is not 



