768 SYSTEMATIC PALEOXTOLOGY 



inferioribus acute serratis, superioribus integerrimis, acutis." Heer, 

 1874. 



This species was described originally by Heer from the Kome beds 

 (Lower Cretaceous) of Greenland and was subsequently identified by the 

 same author from the much later Atane beds (Upper Cretaceous). Daw- 

 son reported it from a number of localities in the Kootenai of British 

 Columbia, and Fontaine and Ward described it from the Lower Creta- 

 ceous of the Black Hills. It is also reported by both Lesquereux and Ward 

 from the Dakota group and by Kurtz from Argentina. It seems very 

 doubtful if these can all refer to the same plant, and the geologic range 

 alone suggests that the earlier and later forms may be distinct. The 

 Lower Cretaceous forms certainly suggest a relationship with those wide- 

 spread types of sterile fronds variously identified as Thyrsopteris or 

 Onycliiopsis, and may be compared with Onyckiopsis goepperti (Schenk) 

 Berry, while those from the Upper Cretaceous suggest Anemia rather 

 than Asplenium and are much like an undescribed Anemia from the 

 Lower Eocene (Wilcox) of the Mississippi embayment areas as well as 

 the widespread Eocene species Anemia haydenii (Lesquereux) and 

 Anemia subcretacea (Saporta) Gardner and Ettingshausen. However, in 

 the absence of representative material from the different horizons, it 

 seems unwise to attempt any segregation at the present time and the 

 synonymy is cited in full for the use of some future student who may have 

 access to enough material to enable an accurate revision and segregation 

 of this so-called species. Attention should also be called to its resemblance 

 to the form occurring in the Upper Cretaceous of Greenland, the Raritan 

 fromation of New Jersey and the Tuscaloosa formation of Alabama, 

 which goes by the name of Dicksonia greenlandica Heer, although the 

 ground for considering it a Dicksonia is as entirely inconclusive as is the 

 reference of the present species to the genus Asplenium. 



In addition to the localities enumerated above, the present species is 

 abundant in the New Jersey and Maryland Raritan, and material that is 

 absolutely identical with the New Jersey material and that from the 

 Dakota sandstone occurs in the lower Tuscaloosa formation of Alabama. 



