Maryland Geological Survey 277 



through the Barremian into the Albian of Portugal. Elsewliere in Europe 

 it has been found in the Wealden of England, Belgium, and Germany, 

 the ISTeocomian near Quedlinburg, Saxony, and in the Barremian of 

 Austria. Forms which are identical, according to Seward (he. cit.) are 

 found in the Uintenhage series of South Africa, while jSTathorst has de- 

 scribed similar remains from the Jurassic- Cretaceous boundary in Spitz- 

 bergen as 8phenopteris sp. A.^ In this country outside of the Potomac 

 it is found in the Kootanie at Great Falls, Montana; in the Shasta beds 

 of California, and in the Lakota formation of the Black Hills. 



The forms identified as this species from the supposed Jurassic near 

 Cape Lisburne, Alaska, have been shown by Knowlton to be forms of 

 Dichsonia. Saporta, in his treatment of the Portuguese forms, leaves 

 them in the genus Splienopteris, but thinks that they are more closely 

 related to certain modern species of Davo2lia than to Onychium. His 

 figures, however, do not bring this out with any degree of certainty. 

 Professor Seward, in discussing specimens from South Africa {loc. cit.), 

 unites with this species the Japanese Jurassic and Cretaceous forms des- 

 ignated as Thyrsopteris elongata Geyler and Onychiopsis elongata Yoko- 

 yama. The reason for the proposed change is the discovery in the Eng- 

 lish Wealden of more extensive material which showed the psilotoides 

 type of pinnule distad and the elongata type of pinnule proximad. 

 It is quite possible that the remains from the English Wealden are 

 all of one species, but it certainly does not follow that the synonymy 

 follows such a disposition. The American remains identified with the 

 elongata type show that the forms with broader segments are not portions 

 of fronds with the distal basal characters of psilotoides, although there 

 is in most ferns more or less diminution in size upward. 



Through the kindness of Prof. Yokoyama the writer has received 

 specimens of elongata from the Jurassic of Kaga, Japan, and these are 

 certainly specifically distinct, especially in the fertile pinnse, from the 

 English forms of psilotoides. They are therefore included in the present 



^Nathorst, Kgl. Svenska Vetens.-Akad., Handl., Band xxx, No. 1, 1897, p. 

 49, pL ii, fig. 14. 



