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. 



