672 



HISTOKICAL GEOLOGY. 



species are not related in fructification to the Lycopods or Equiseta, or to 

 any known group of Cryptogams. 



2. Gymnosperms of the Order of Cycads. — The character and fruit of 

 Cordaites has been well illustrated by Lesquereux from specimens obtained 

 at Cannelton, Pa. Fig. 1057 shows the Cycad-like foliage ; and Fig. 1057 a 



1057. 



Fig. 1057, Cordaites costatus ; 1057 a, fruit, with a portion of the attached stem. Lesquereux. 



represents fruit which occurs at the same locality, and is found there so 

 closely associated with the leaves as to be probably of the same species. 

 Lesquereux figures the leaves and fruit also of C. Mansfieldi from this 

 locality, a species with much broader leaves, and nuts of a smooth 

 obovate form, 2\ inches long. 



The Sigillarids are referred to this division of the Gymnosperms by Ke- 

 nalt and Dawson, but to the Lycopod tribe by Williamson and most authors. 



