EXPLANATION OF PLATE XVIII 
Fossil Fucoids from Pogibshi Island, near Kadiak 
Village, Alaska 
Natural size 
Figs, i and 2. Gilbertina spiralis gen. et sp. nov. Page 141. 
1. The largest specimen seen. The elliptic outline probably is 
due to compression. 
2. The smallest specimen in the collection. It is important be¬ 
cause of the irregular folds of the outer whorls. 
3. Gyrodendron emersoni gen. et sp. nov. Page 140. (See 
also plate xix.) 
A small specimen, considering that it is three times bifurcated. 
4. Chondrites alpestris Heer. Page 136. 
View of the only specimen of this species seen. It is an 
empty mold of the exterior. 
5. Retiphycus hexagonale gen. et sp. nov. Page 139. 
View of the unique specimen upon which this genus and 
species is founded. The specimen is restored in the 
shaded central part of the figure. 
