28 THE OLDEE MESOZOIC FLOEA OF VIEGINIA. 



various plants with Pecopteris Whitbiensis. The sterile forms of the Jurassic 

 Acrostichides and Cladophlebis have a good many features in common, and 

 in the absence of fructification all these plants, however diverse, would be 

 reduced to Pecopteris Whitbiensis if this custom be followed. Certainly 

 Professors Rogers and Bunbury would in that case be justified in announc- 

 ing Pecopteris Whitbiensis as found in the Richmond Coal Field. Again, it 

 seems to me that Lindley and Hutton's Pecopteris Whitbiensis is a very dif- 

 ferent plant from that of Brongniart. Schimper, I think, went as far as 

 was proper when he proposed to group the Jurassic ferns with no known 

 fructification, having a resemblance to Pecopteris Whitbiensis, as plants of 

 the type of P. Whitbiensis. He very properly later agreed with Saporta in 

 assigning a generic value to the common features of these plants, and 

 grouped them under the genus Cladophlebis. 



Acrostichides linncecefolius seems to be a rare plant. I have never seen 

 either the sterile or fertile forms anywhere but at the old Cowry Shaft. 

 The only other locality yielding it, so far as I know, is the Blackheath 

 Mine, from which Bunbury procured his specimen. The Blackheath occurs 

 in the same part of the coal field as the Gowry. 



Formation and locality. — Found at the Cowry and Blackheath in the 

 roof of the main coal. 



Since the above was written I have been so fortunate as to find among 

 the specimens collected by Professor Rogers, while engaged in his survey 

 of Virginia, and placed in the geological collection of the University of 

 Virginia, a magnificent slab with an impression, finely preserved, of Acros- 

 tichides linncecefolius. This impression is 40 centimeters long, and shows a 

 fragment of what seems to be a compound pinna. The rachis does not 

 diminish much in diameter from the base to the summit of the specimen, 

 and the great length of the uppermost ultimate pinnse, viz., nearly 20 cen- 

 timeters, together with this fact, seems to indicate that, large as the frag- 

 ment is, it is only a small portion of the pinna from which it was derived. 

 The ultimate pinnae of the lower and middle portions of the specimens 

 must have been over 20 centimeters long, and hence the width of the speci- 

 men must have been over 40 centimeters. I have drawn two pinnae from 

 the lower part of the impression and two from the upper, as the specimen 



