OLDER POTOMAC OF VIRGINIA AND MARYLAND. 551 



siderable portion of the termination of a penultimate pinna, with a 

 number of ultimate pinnse and pinnules. This specimen retains only 

 the imprint of outlines on pale-pink, friable, sandy shale, the material 

 which at this locality gives the best fossils. None of the vegetable sub- 

 stance is retained. PI. CXV, Fig. 8, represents, in the same kind of 

 rock material, a portion of a principal rachis with several minor pinnse 

 attached, carrying ultimate pinnae reduced to pinnules. The latter, in 

 some cases, are verj^ distinctly preserved. Both the specimens fagiu^ed 

 were collected on September 2, 1896, and are in the National Museum. 



Ginkgo ? acetaeia Ward n. sp." 



PL CVIII, Fig. 12. 



Seed of Ginkgo. ? The only trace of a probable Ginkgo in the flora 

 of the Lower Potomac of Maryland is shown in a nut-like seed which 

 may, however, really be a seed of Baieropsis. It is a nutlet, 12 mm. long 

 and 9 mm. wide. It is smooth on the surface, with traces of the former 

 fleshy envelope. In shape it is broadly oval, and is narrowed to a short 

 beak at one end, or rather to an acute point, the point being much like 

 the tip of the seed of the living Ginkgo biloba. It is smaller than the 

 seed of G. biloba, but is decidedly larger than the small ones of the Gink- 

 gos of the Jurassic of Oregon, described in this paper (see p. 126, PI- 

 XXXIII, Figs. 12-19). The trace of the fleshy envelope is in the 

 form of a depressed rim around the seed. The specimen was collected 

 by Mr. Bibbins in October, 1895, and is No. 6084 of the museum of the 

 Woman's College. 



Leptostrobus longifolius Fontaine. 

 PI. CXVI, Fig. 1. 



Twenty-six specimens of a plant which is certainly L. longifolius 

 were found at this locality. The species ranges from the bottom to the 

 top of the Lower Potomac strata of Virginia. It is most abundant in 

 the beds of the Dutch Gap locahty, which are slightly lower than those 

 showing plants at Fredericksburg. PL CXVI, Fig. 1, represents the 

 most complete specimen. This shows a number of tufts of linear leaves, 



« Professor Fontaine assigns no specific, name to this form. From principles that I have frequently set 

 forth it should have one, however provisional, and 1 name it in allusion to the locality. — L. F. W. 



