512 MESOZOIC FLORAS OF UNITED STATES. 



Cladophlebis virginiensis Fontaine. 



PI. CXI, Fig. 7. 



1889. CladopMehis virginiensis Font. : Potomac Flora (Monogr. U. S. Geol. Surv., 

 Vol. XV), p. 70, pi. iii, figs. 3, 4, 4a, 5, 5a, 6, 7, 7a, 8, 8a; pi. iv, figs. 1, la, 

 .3, 3a, 4, 4a, 4b, 5, 6. 



This plant is not common, only 2 specimens occurring. One of these 

 is a fragment of penultimate pinna with a rachis 5 mm. wide. It shows 

 the basal portions of two ultimate pinnae which carry very large pinnules. 

 These show, toward their tips, a slight dentation, a feature not often seen 

 in the specimens previously found. It is shown on PI. CXI, Fig. 7, of this 

 paper. 



Drtopteris fredericksburgensis (Fontaine) Knowlton. 

 PI. CXII, Fig. 2. 



1889. Aspidium fredericksburgense Font. : Potomac Flora (Monogr. U. S. Geol. 

 Siu-v., Vol. XV), p. 94, pi. xi, figs. 1, la, 2, 2a, 2b, 3, 3a, 4, 4a, 5, 6, 6a. 



1898. Dryofteris fredericksburgense (Font.) Kn. : Bull. U. S. Geol. Surv., No. 152, 



p. 92. 



Five specimens of this species were collected, 4 on April 16, 1893, and 

 1 doubtful one on July 17. The best specimen is a well-preserved por- 

 tion of a penultimate pinna with the basal portions of several ultimate 

 pinnse. These cany man}^ pinnules. It is the form with entire pinnules, 

 and is shown in PI. CXII, Fig. 2, of this paper. 



Frenelopsis ramosissima Fontaine. 

 PL CXI, Fig. 8. 



1899. Frenelopsis ramosissima Font.: Potomac Flora (Monogr. U. S. Geol. Surv., 



Vol. XV), p. 215, pis. xc-v-xcix; pi. c, figs. 1-3; pi. ci, fig. 1. 



This species jdekls 7 specimens, some of them good. The most com- 

 plete one is composed of several antepenultimate twigs, carrying a numl^er 

 of penultimate ones. These have a number of ultimate twigs, all prett}' 

 well preserved. This is shown in PL CXI, Fig. 8. This fossil is highly 

 characteristic of the Fredericksburg or Eappahannock horizon in the 

 Potomac flora, being practically confined to it. It is, then, important as 

 indicating that the Chinkapin Hollow horizon is the same. 



