FOSSIL PLANTS. 451 



HALONIA TUBERCULATA ? Brgt. 



PL xxix, fig 1. 



STEM about three inches broad, flattened by compression to 

 one inch, bearing large, round, elevated tubercles, hollow in 

 the middle, or funnel-shaped, with a round convex point or 

 small mammilla in the center. The specimen is not only 

 decorticated, but corroded by sulphuric acid, and nothing is 

 seen of the cicatrices between the tubercles but irregular, un. 

 dulate wrinkles, crossing each other without any definite di- 

 rec*ion. The hollow tubercles look like large cicatrices of 

 Stigmaria. 



As the tubercles of the species of Halonia have never been described hol- 

 low in the center, our plant is doubtfully referred to it. The deterioration of 

 the surface has evidently not produced the cavities of the tubercles, for the in- 

 ternal surface is smooth, regularly inclined downwards, bearing at the bottom 

 a discernible vascular scar, similar to that of a Stigmaria. This species may 

 be a Stigmaria, though the cicatrices are at least double of those of S. umbo- 

 nata, Lesqx. 



From the Chester group, Pope county. 



GENUS STIGMARIA, Brgt. 



111. Geol. Rep., vol. ii, p. 447. 



STIGMARIA ELLIPTICA, Sp. nov. 



PL xxix, fig. 2. 



STEM thick, half a foot broad, flattened to one inch; cica- 

 trices placed in regular spiral quaternate order, elliptical, more 

 or less elongated and proportionally narrow, with a central 

 nearly round, small mammilla, marked in the middle by a 

 vascular point. The specimen is covered with a thin coat of 

 coaly matter, which has filled the scars, where it has an in- 

 creased thickness, obliterating generally the mammillae. These 



