CARBONIFEROUS PERIOD. 



339 



are also common in the United States, occurring in the Rhode Island coal fields 

 as well as elsewhere. Alethopteris Serlii Gb'pp. is another common species of 

 the Upper Coal measures, which is found also in Europe. Fig. 580, Cyclopteris 

 elegans Lsqx., found in the Shamokin Coal hed, Pennsylvania. 



In Arctic America, on Melville Island, impressions of a Sphenopteris have 

 been observed in connection with the coal. 



Figs. 576-583. 



Fig. 576, Neuropteris Loschii ; 577, Neuropteris hirsuta ; 578, Sphenophyllum Schlothei- 

 mii; 579, Pecopteris arborescens ; 579 a, a portion of the same, enlarged; 580, Cyclopteris 

 elegans; 581, Asterophyllites ovatus, with the nutlets in the axils of the leaves; 582, A 

 sublevis; 583, Calamites cannseformis ; 583 a, surface-markings of same, enlarged. 



The genus Odontopteris is mostly of the Lower Coal measures. Fig. 584, 

 portion of a frond of 0. Schlotheimii, from Pennsylvania and Europe; the whole 

 frond is tripinnately divided, and of very large size. All the species of Hymeno- 



