136 ALASKA GEOLOGY 



the post-cardinal region of /. concentrica constitutes another feature 

 so far unknown in Posidonomya. 



Locality. Woody Island, Kadiak, on the shore facing Chiniak 

 Bay, Alaska. 



Collector. W. H. Dall. 



FUCOIDES 



Genus Chondrites Sternberg. 

 Chondrites divaricatus Fischer-Ooster. 



Pl. XVI, figS. I, 2. 



Chondrites divaricatus FISCHER-OOSTER, Foss. Fucoiden, p. 45, 1858. 

 HEER, Flora Foss. Helvetiae, p. 107, taf. XLI, figs. 6, 7, and taf. 

 XLII, figs. 11,12, 1877. 



Two specimens in the material gathered at Kadiak Island appear to 

 fall within the limits of this species. They occur as delicate, slightly 

 glossy, black, widely divaricating ramulets in an arenaceous slate. 

 The branching stems have a width of from 0.45 mm. to 0.6 mm., and 

 divide both dichotomously and pinnately at frequent though variable 

 intervals. The lateral divisions are short and not appreciably thick- 

 ened at their extremities. 



In one of the two specimens the stems are a trifle thinner and the 

 divisions more abundant than in the other. This approaches C. 

 intricatus (Brongniart) Heer, a common Eocene fossil in Switzerland 

 and elsewhere in Europe, yet not near enough to justify its separa- 

 tion from C. divaricatus. The latter is not uncommon in the Upper 

 Lias of central Europe. 



Locality. Pogibshi Island opposite the village of Kadiak, Alaska. 



Collectors. G. K. Gilbert, B. K. Emerson, Charles Palache. 



Chondrites alpestris Heer. 



Pl. XVIII, fig. 4. 



Chondrites alpestris HEER, Flora Foss. Helvetiae, p. 109, taf. XLII, figs. 

 13-16, 1877. 



Plant caespitose, apparently not spreading in one plane but giving 

 off branches in all directions ; divisions very frequent, diverging very 

 slightly, oftener dichotomous than pinnate ; branches varying from 

 0.5 mm. to i.o mm. in width, apparently terminating obtusely. 



C. alpestris is so strikingly different from nearly all the other 

 species of this prolific genus, and at the same time is signalized by 

 such obvious peculiarities, that we have no doubt concerning the close 

 relations, if not the identity, of the Alaskan specimen here described 



