42 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA. 



borders, and the middle is generally marked by a depression which seems to 

 indicate a fistulous character of the stem and its divisions. 



Habitat. — Base of" the Lignitic formations, Raton Mountains, New 

 Mexico. 



Chondrites bnlbosns, Leaqz. 



Plate I, Fig. 14. 



Chondrites lullosm, Lesqx., Auuual Report, 1872, p. 273. 



Frond flattened, irregularly, subpinnately divided in opposite or alternate branches, close to each 

 other, or distant, short, inflated, some of them like irregular tubercles. 



Mere fragments of the brandies of this species could be obtained for 

 illustration and description. The mode of division is very irregular; gener- 

 ally the main axis is slightly larger than the primary branches, three to five 

 millimeters broad and irregularly dichotomous. The divisions, however, are 

 directed either in right angle or upward and downward in the same fragment, 

 and sometimes linear, sometimes inflated, taking the most diversified and 

 irregular appearances, or inordinately inflated and narrowed. This species 

 finds analogous representatives in Halymenites varius and other Algoids, 

 described by Sternberg under the same generic name, from the Jurassic for- 

 mations; the Tertiary species differing merely by its smooth surface and the 

 more distinctly inflated branches. 



Habitat. — Raton Mountains, near Trinidad, New Mexico; base of the 



Lignitic formations. 



FUCUS, Linn. 



Fucus lignitiim, Lesqx. 

 Plate LXI, Figs. 24 and 24 a. 

 Fucus lignituvi, Lesqx., Annual Report, 1874, p. 296. 



Frond flattened, irregularly dichotomous ; branches diverging obliquely ; branchlets short, terminal, 

 linear, divaricate, tufted, forking at the point. 



The fragment figured here is the only part of the plant represented 

 upon the specimens. The lowest branches are four millimeters broad at 

 the base, but the size of the branchlets diminishing nearly one-half at each 

 dichotomous division, the terminal ones are very slender, scarcely half a milli- 

 meter broad. The upper divisions are like the first ones, short, split or forking 

 at the point, and divaricate. The substance is membranaceous and yellowish, 

 We have here evidently mere fragments of apparently large compact fronds 

 like those of the living Fucus canaliculaius, Agh., common along the coasts of 

 the Baltic Sea, and which appears closely related, by its membranaceous con- 

 sistence, its mode of division, and the form of its branchlets, to the species 



