UTICA SLATE AND HUDSON-RIVER GROUP. 
2GI 
FOSSIL PLANTS OF TIIE UTICA SLATE AND HUDSON-RIVER GROUP. 
Wc find in this group several well marked species of marine plants, with other forms 
simulating, if not actually, organisms of this class. The prevailing forms are similar to those 
of the preceding strata, but the same species have not been recognized. The nature of the 
sediment, and the condition of the ocean bed, were favorable to the development and 
growth of this kind of vegetation; for we find, in almost every locality, evidences of its 
existence. As our researches have been principally directed to the discovery of animal 
fossils, little examination has been made in situations most favorable for the preservation 
of these plants; and we may anticipate a very large accession to the number of species, 
when careful explorations are made. The species already obtained show a considerable 
variety of form, and it is evident that we are but commencing our knowledge of the 
ancient marine flora. 
The two following species appear to be quite new, and to require a generic designation. 
Genus S P H E N 0 T H A L L U S. 
[Greek, a 'p^v, a wedge, and &uXkog, a branch or frond; in allusion to the form of the leaves.] 
Character. Plant consisting of a stem, with diverging wedge-form leaves, or of detached 
leaves having this form. Leaves apparently succulent or thickened, and sometimes sub- 
coriaceous. 
It will probably be found that plants of this character are restricted to Silurian, and 
perhaps Lower Silurian strata. 
314. 1. SPHENOTHALLUS ANGUSTIFOLIUS (n.sp.). 
Pl. LXVIII. Fig. 1. 
The specimen is a fragment, consisting of a stipe or stem, to which are attached elongated 
narrow cuneiform leaves. These leaves appear to proceed in tufts, and are accompanied 
by other smaller and narrower ones about their base. The stem presents no distinct 
markings, though there are several obscure impressions which may have been the point 
of attachment for leaves. The leaves are obscurely striated, though nothing like a veined 
structure can be distinguished. 
Tire fragment has much the appearance of the terminating portions of the Catamites; 
and it is difficult to believe that it is not a land plant, though in a position so far below 
where anything of the kind has heretofore been discovered. 
Position and, locality. The specimen figured, with another obscure fragment, were 
obtained from an authentic locality, between the village of Canajoharie, on the Mohawk, 
and Schoharie village, by Mr. Lyman Wilder, of Hoosick falls.* 
* I am thus particular in stating the locality, and my authority for the specimens, though the succeeding species 
serves to establish the fact of its occurrence in this position. 
