YAKUTAT FOSSILS 139 



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

 Collector. G. K. Gilbert. 



Genus Cancellophycus Saporta. 

 Cancellophycus rhombicum sp. nov. 



Pl. XX, fig. I. 



Of this fossil the collections before us contain only the specimen 

 figured on pi. xx. It lies on the flat surface of a block of slate and 

 probably represents only a part of an originally much larger expan- 

 sion. That this was ever sack-like in form, as is believed of the typi- 

 cal species of Cancellophycus, is very doubtful. Instead, the evidence 

 of the specimen all tends toward proving that it was originally a large, 

 simple, flabelliform expansion. This probable difference in growth 

 might justify another generic arrangement, but as some at least of the 

 species referred to the genus by Saporta indicate a similar habit of 

 growth, and as the general structure agrees very well with that of the 

 species in mind, notably C. reticulare Sap., it seems best, for the 

 present at least, to refer the Alaskan species to the same genus. 



The surface of the specimens is covered with branching and inter- 

 woven knotted ribs and threads, leaving, according to the degree of 

 regularity in which they cross or unite with one another, either elongate 

 shapeless meshes or more or less regularly rhomboidal ones. Along 

 the lower edge the ribs are very much stronger, and here the bifurca- 

 tions are numerous, the size of the branching threads being soon re- 

 duced to an average thickness of less than 0.5 mm. The meshes 

 exhibit a fine longitudinal striation. 



C. rhombicum seems to be closely related to C. reticulare Saporta, 1 

 from the Lower Oolite of the Jurassic of France. It may be dis- 

 tinguished, however, at once by the much greater delicacy of its ribs 

 and smaller rhomboidal meshes. 



Locality. Pogibshi Island, opposite the village of Kadiak. 



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



Retiphycus hexagonale gen. et sp. nov. 



pi. xvni, fig. 5. 



Plant ? forming retiform expansions of unknown dimensions ; meshes 

 somewhat irregularly hexagonal, averaging six in 25 mm. ; separating 

 walls about i.o mm. thick, rounded. 



The composition of this fossil seems to be precisely as in the other 

 ' fucoids ' found at Kadiak, and if the latter are to be regarded as 



Franc., 2 sen, Veg., T. i, p. 142, pis. 7 et 8, fig. i, 1873. 



