tJTICA SLATE -AND HUDSON-RIVER GROUP, 263 



317. 5. BUTHOTREPHIS ? FLEXUOSA. 



Pi.. LXIX. Figs. 1 a, b, c. 



Fucoidet rigida & ftexuosa. Emmons, Tac. System, 1844, pag. 67, pi. 5, figs. 2 & 3. 

 — — &. — Id. Agr. Report, 1846, pag. 69, pi. 17. 



Frond compressed, somwhat irregularly branched ; stems and branches extremely 

 compressed. 



This species presents much variation of character, owing in part to the condition of 

 the slate in which it is imbedded. The two species of Dr. Emmons are not separable by 

 any established characters, and we find numerous intermediate forms. The specimens 

 usually consist of a thin carbonaceous film upon the surface of the soft slate ; and slabs 

 of several feet square are often nearly covered with fragments, which appear to have 

 been of a less succulent character than most of the preceding species. 



This is one of the species regarded by Dr. Emmons as typical of the slates of the Taconic 

 system, but I can find no evidence to support this assumption. The locality, though con- 

 taining no characteristic fossils of the Hudson-river group, is surrounded by authentic 

 exposures of these rocks, and the lithological character is the Sfime. Further examination 

 will doubtless enable us to obtain this species in other localities of the group. 



Fig. 1 4. A large fragment, with numerous branches or leaves. The specimen appears to have been 



long macerated before it was imbedded. 

 Fig. 1 6. A specimen in the same condition as the last, with the branches less diverging. 

 Fig. 1 e. A fragment of stone, with two smaller specimens retaining more of the original substance of 



the plant 



Position and locality. In the slates of the Hudson-river group, M' Arthur's quarry, 

 Jackson, Washington county. {State Collection.) 



318. 5. PAL^OPHYCUS VIRGATUS (n. «;>.). 



Pl. LXX. Fig. 1. 



This species is only seen in fragments of long rigid stems, of nearly equal diameter. 

 It appears to have been succulent or tubular, and is always compressed in the stone. 

 Fractured or weathered surfaces of the arenaceous shales often present great numbers of 

 these fragments, imbedded in great confusion. 



The species bears some analogy to the P. simplex of the Trenton limestone ; but it is 

 impossible to indicate characters either to assimilate or distinguish them. It can be readily 

 identified in the rock, from its resemblance to flattened fragments of stems of succulent 

 plants. 



Position and locality. This species is abundant in the shales of this group, in the neigh- 

 berhood of Union village and Salem, in Washington county. (State Collection.) 



