336 



PALEOZOIC TIME — CARBONIFEROUS AGE. 



accumulated, while the Lepidodendra and Conifers, though not ex- 

 cluded from the marshes, covered the drier hills and plains of the 

 continent. Most of the Sigillariae grew up as simple trunks to a 

 height of thirty to sixty feet, without branches. The surface and 

 summit were covered with long, narrow leaves in great numbers ; 

 and out of these leaves, found separate, the genera Poacites and 

 Cyperites have been made. The trunk is usually ribbed vertically, 

 and the scars are arranged along the ribs. The name of the genus 

 alludes to the scars, and is from the Latin sigilla, seals. In both 

 this group and the preceding, the appearance of the scars of the 

 same species varies much with age, and upon the opposite sides of 

 the bark the same scar is wholly different, as shown in figs. 568 

 and 569, in the part of each of which to the right an impression 



Fig. 568, Sigillaria oculata ; 569, S. obovata ; 570, Stigmaria ficoides. 



of the inner surface of the bark is shown. The plant is proved 

 to have been of close texture through the interior of the trunk, 

 and still may have had a rapid growth. Stumps made hollow 

 by decay within, and now filled with sand and clay and fossilized, 

 are common in the Coal measures. Of many such, only casts in 

 sand, showing an impression of the scarred exterior, remain. 



Fig. 568 represents the Sigillaria oculata, from Trevorton, Pa. ; 569, S. obovata, 

 from Pennsylvania and Kentucky. 



3. Stigmarice. — The Stigmarice were originally described as the re- 

 mains of trees related to the Sigillarice. The surface-impressions are 

 very different, being simply scattered rounded depressions or pro- 

 minences ; and to each there is sometimes a long, leaf-like append- 

 age, as in fig. 570, which represents a portion of a branch. But the 

 branching roots of both Sigillarise and Lepidodendra have been 



