668 



HISTORICAL GEOLOGY. 



Devonian, or a related species, is commoii in some portions of the Pottsville 

 conglomerate in Kentucky and elsewhere. 



1. Vascular Cryptogams. — Lycopods. The Lepiclodendron trees had the 

 exterior embossed with oblong scars, as in Figs. 1033, 1034, and 1036. 



1033. 



1033-1035. 



1034. 



1035. 



Fig. 1033, Lepldodendron aculeatum ; 1034, Lepidodendron clypeatum ; 1035, Halonia pulchella. Fig. 1033, Fair- 

 child ; 1034, 1035, Lesquereux. 



Leaves like those of the Spruce or Pine occasionally occur on the fossil stems 

 (Fig. 1040); and in some foreign specimens of L. Sternhergii Brgt., from Aus- 

 trian coal-beds, they are over a foot long, and as closely crowded on the 

 branches as in any modern pine. The Lycopodium dendroideum of modern 

 forests, if magnified largely, would give a good idea of the aspect of the 



10.36. 



1036-1038. 

 1037. 



rr \^ 



I© 



w^ 







1 







Fig. 1036, Lepidodendron Veltheimanum ; 1037, Sigillaria Sillimam ; 1038, S. Pittstonana. Lesquereux. 



trees. The cones of Lepidodendrids were long, and much like those of a 

 living Lycopod, and are referred to under the name Lepidostrobus, and the 

 leaves of the cone under that of Lepidophyllum. The stems, called Lycopo- 



