YAKUT AT FOSSILS 137 



and figured with the Swiss Upper Liassic types of the species. Our 

 specimen is a hollow mold of the exterior in a slaty sandstone. 



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



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



Genus Palaeodictyon Heer. 

 Palaeodictyon magnum laxum subsp. nov. 



Pl. XV, fig. I. 



Cfr. Palaodictyon magnum HEER, Flora Foss. Helvetise, p. 160, taf. LXIV, 

 fig. 9, 1877. 



The remains of this plant appear as glossy, flat, irregularly convo- 

 luted, rarely inosculating bands 2 mm. to 3 mm. wide, on fresh sur- 

 faces of a dark slate. The bands evidently are mere fragments that 

 originally may have been connected to form a very loose and irregu- 

 larly meshed network. 



At first sight we were inclined to refer these Alaska specimens to 

 Heer's P. magnum without qualification, they being perhaps suffi- 

 ciently like certain portions of the figure published by Heer of this 

 Eocene (Flysch) species to justify their identification. Closer com- 

 parisons, however, satisfied us that the growth of the Alaskan form 

 was more irregular and very loosely reticulated, so that it seems advis- 

 able to distinguish it as a subspecies at least. 



Locality. Woody Island, near the village of Kadiak, Alaska. 

 Collector. W. H. Dall. 



Palaeodictyon singulare Heer. 



Pl. XV, fig. 2. 



Palaodictyon singulare HEER, Urwelt der Schweiz, p. 245, taf. x, fig. 10, 

 1865, and Flora Foss. Helvetiae, p. 160, taf. XLIII, fig. 21, taf. LXIV. 

 figs. 5-8, 1877- 



This delicate form is associated with P. magnum var. laxum, but 

 will be distinguished at a glance by its smaller size and much closer 

 intertwinings. The bands usually are a trifle less than i mm. wide 

 and but rarely exceed that width, and they bend in and out and over 

 cue another so rapidly that they appear to form a close but always 

 very irregular network. 



This form has seemed to us to agree too well with some of Heer's 

 figures of P. singulare to be distinguished even as a variety. In 

 Switzerland the species occurs, sometimes in association with P. mag- 



