15 



Alet. 



Alethopteris sullivaiiti. See Callipteridium suUivanti. 

 XIIL 

 Alethopteris virginiana. Fontaine & White, Geol. Siir. 



Pa., PF, 1880, page 88, plate 32, figs. 1 to 5; 33 figs. 1 to 4 

 Finnc'© very long, because fragments of one-foot length are 

 found, but always single fallen ones, often the only plant pre- 

 served by thousands in the upper fine parting shale (under top 

 bench) of the Waynesburg coal, at Cassville. In the roof 

 shale of the top coal bench, full of all other plants, this Ale- 

 thopteris is wholly absent at Cassville and elsewhere. Has a 

 great variety of forms running into each other. Plate 33, fig. 

 1, shows swellings (? fruits). Compare Lesq. 111. Rt. 4, pi. 10, f. 

 6, for similar fruitage to A, inAata. Upper coal measures. — 

 XVIL 



Note. — The genus Alethopteris includes many of the most 

 common ferns of the coal age, especially Aleth. lonchitica^ 

 which abounds in all coal regions, and seems to have been as 

 common in the coal swamps as the Pteris aquilina is now in 

 Europe and America. The characteristic feature of its leaflets 

 is that they adhere to the little stalk by their whole base and 

 touch each other at their bases. Dawson. 



