J. S. Newberry — Flora of the Great Falls Goal Field. 197 



List of Potomac species occurring elsewhere. 



Equisetum Lyetti Mant., Wealden, Germany. 

 Pecopteris socialis*? Heer, Atane, Greenland. 

 Pecopteris Browniana Dunk., Wealden, Germany. 

 Sphenopteris Mantelli Brongn., Wealden, Germany. 

 Aspidium Oerstedi*? Heer, Atane, Greenland. 

 Aspidium Dunkeri Schimp., Wealden, Germany. 

 Gleichenia Nordenshioldi Heer, Kome, Greenland. 

 Dioonites Buchianus Schimp., Wealden. Germany. 

 Sequoia Reichenbachi Heer, Cretaceous [general]. 

 Sequoia subulata Heer, Kome, Greenland. 

 Sequoia ambigua Heer, Kome, Greenland. 

 Sequoia rigida Heer, Kome, Greenland. 

 Sphenolepidium Kurrianum Heer, Wealden, Germany. 

 Sphenolepidium Sternberg ianum Heer, Wealden, Germany. 



Potomac Plants in Great Falls Group. 



Sphenolepidium Virginicum F. 

 Carpolithus Virginiensis F. 

 Thyrsopteris rarinervis F. 

 Aspidium Fredericksburg en se F. 

 Thyrsopteris insignis F. 

 Thyrsopteris brevipennis F. 

 Sequoia Reichenbachi Heer. 

 Pecopteris Browniana Dunk. 

 Gladophlebis distans F. 

 Pecopteris microdonta F. 

 Thyrsopteris brevifolia F. 

 Gladophlebis parva F. 

 Gladophlebis constricta F. 



Great Falls Plants in Kootanie Group, Canada. 



Sequoia Smittiana Heer. 

 Zamites Montana Dawson. 

 Zamites acutipennis, Heer. 



Great Falls Plants in Kome Group, Greenland. 



Sequoia Smittiana Heer. 

 Oleandra arctica Heei\ 

 Zamites acutipennis Heer. 

 Zamites borealis Heer. 

 Sequoia Reichenbachi Heer. 

 Sequoia gracilis Heer. 



* The materials on which Prof. Fontaine based the identification of these spe- 

 cies are insufficient for satisfactory comparison ; and while it is not impossible 

 that the life of one or more species may have stretched over all the interval be- 

 tween the beginning and end of the Cretaceous age, stronger evidence of this fact 

 than any we yet have must be furnished before we can consider it as established. 



