94 THE OLDER MESOZOIC FLOEA OF VIRGINIA. 



the rhombic type in A. microphyllus, and the oblong-ovate, subfalcate type 

 in A. densifolius. A. densifolius has some features in common with Pecop- 

 teris Haibumensis, Lind. & Hut., from the lower Oolite of Yorkshire. It 

 has the same thin, membranaceous texture, and slender, copiously branched 

 nerves, while the shape of the pinnules is something like that of the Oolitic 

 plant. A. microphyllus might be compared with Sphenopteris Bossertiana, 

 Presl, from the Rhsetic of Germany. In any case these two plants belong 

 to a type which is, in the main, characteristic of strata younger than the. 

 Trias. 



Mertensides bullatus, by its fructification, belongs to the Gleicheniacese, 

 and seems to have no very near relationship with any previously described 

 plant. Asterocarpus Virginiensis also cannot help us in fixing the age of the 

 strata containing it. The same may be said of A. penticarpus, as it is too 

 fragmentary and poorly preserved to disclose with certainty its true char- 

 acter. Pecopteris rarinervis may be omitted for the same reasons. 



The genus Cladophlebis is characteristic of the Rhaetic and Jurassic. 

 The five species of this genus not found in European strata, viz., C. auricu- 

 lata, C. ovata, C. microphylla, C. pseudowhitbiensis, and C. rotundiloba, have a 

 decided Jurassic facies, and some of the species would be placed by some 

 authors in the group of Alethopteris or Cladophlebis Whitbiensis. The orig- 

 inal Pecopteris Whitbiensis of Lindley & Hutton, and that of Brongniart, as 

 it seems to me, if they are the same species, belong to the genus Clado- 

 phlebis, as Schimper has stated. Heer has taken the name Whitbiensis for 

 certain species of Asplenites described from the Jurassic of Amur. It would 

 seem that there is no warrant for assuming, as Heer has done, that the orig- 

 inal species Pecopteris Whitbiensis is a species of Asplenites. The fructifica- 

 tion of this plant has not been found, and until it is found it should remain 

 in the genus Cladophlebis. 



The small plant, C. microphylla, has some points in common with 

 Gleichenia Bindrabunensis, or Pecopteris gleichenoides of Oldham & Morris, 

 from the Rajmahal Group of India, but it is a larger plant. The number of 

 species of Cladophlebis in the Virginia Mesozoic lends to the flora a Jurassic 

 facies. 



The two species of Pseudodanseopsis are more like the Triassic genus 



