OLDKK I'OTOMAC OF V1R(;1MA AND MAin LAND. 553 



the \\'()niair,s CoUofiC of lialtiniorc. This f(>ni is tho most al)un(hui( 

 fossil ill the collectioii made by Professor Ward and Mr. I5il)l)ins. 1'. 

 virgmiensis has a characl(>r which, even in small specimens, may he 

 easily distinguished. Il is widely distribut(>d both areally and \-erlically 

 in the Lower Potomac formation of \'irt;iiiia, being found in the highest 

 and the lowest l)eds. It is most common at the Virginia locality " Road- 

 side near Potomac Run," on the I'rf^dericksburg or Piappaliannock 

 horizon. 



SeLAGINELLA MAHYLAXDllA Fi)nlailH' n. sp. 



PI. CXV, Figs. '.). 10. 



The specimen found at the Vinegar Hill locality of this new species 

 of Selaginella is quite distinctly preserved, so as to show its character 

 well. The parts shown are several small fragments of penultimate twigs. 

 The penultimate branch forks in a dichotomous manner sympodially, 

 one branch in the forking being more developed than the other and con- 

 tinuing the twig, giving renewed branching. The minor branch in each 

 case becomes an ultimate one. The longest of the i)enultiniate twigs is 

 only 12 mm. long, while the wddth, including the leaves, is only 2 mm. 

 The leaves shown are minute in size, arranged in two rows, expanded in 

 the same plane, and laterally' attached. No leaves show^ on the upper 

 surface, })crhaps because they were carried away in splitting the shale. 

 The lateral nerves are leathery in textiu'e and w-ell preserved. They 

 have a distinct midnerve and are attached by a narrowed portion of the 

 base. They are slightly cordate at base and are widest near the base. 

 In general form they are ovate-acuminate and terminate with a well- 

 preserved awn. The leaves are sometimes slightly falcate. The speci- 

 men is shown natiu'al size in PI. CXV, Fig. 9, and enlarged three diame- 

 ters in Fig. 10. It was collected by Mr. Bibbins in October, 1895, and 

 is No. G148 of the Woman's College. 



VlTIPIIYLLUM MULTIFU)IM FontalllO. 



PI. VXIX, Fig. 5. 



1889. VitiphyUurn muUifidum Font.: Potomac Flora (Monogr. U. S. Geol. Surv., 

 Vol. XV), p. :>()<), pi. clxxxii, figs. 1-9. 



As above remarked, this specimen, the only one found at Vinegar 

 Hill, occurs on the same piece of shale as the Celastropliyllum obovatum. 

 It is noteworthy as being the only ca.se of the occurrence of this species 



