142 
ALASKA GEOLOGY. 
in the much less regular convolution of the cord-like fossil. The 
trend of the variation is toward Helm in th op sis Heer, and Helmin- 
thoida vaga might, with perhaps equal propriety, be referred to that 
genus. 
Heer describes four species of Helminthoida from the Eocene of 
Switzerland, and so far as we know the genus has not been heretofore 
met with in older rocks. 1 One of Heer’s species, H. appendiculata , 
presents a peculiarity in the appendical prolongation of the closed 
end of the loops, but in other respects resembles H. vaga of this 
paper. Our H. subcrassa and H. exacta may be compared with 
Schafhautl’s II. crass a , but both are distinguished by obvious differ¬ 
ences. As to II. abnormis , it stands somewhat apart, yet may be 
compared with certain varieties of H. labyrinthica Heer. 
Concerning the nature of these and other trail-like fossils, we are 
wholly satisfied of their organic origin, while the fact that they often 
lie over each other and sometimes are piled together like tangled cords, 
proves, we believe, conclusively that they are not trails. Considering 
their organic nature as established, some provisional position must be 
assigned to them in nature until something definite concerning their 
structure may be learned. In the mean time we are quite willing to 
follow Heer and others, who view them provisionally as marine 
plants, despite the fact that no corresponding algae are known in the 
present seas. 
Helminthoida exacta sp. nov. 
pi. xvi, fig. 5. 
The remains of this supposed marine plant resemble a convoluted 
cord, about 1.5 mm. in thickness, folded very regularly so as to form 
equal, narrow, slightly curved loops about 18 mm. in depth and aver- 
aging 1.5 mm. in width. The imperfect specimens at hand indicate 
that as growth proceeded the successive loops increased veiy gradually 
in length. 
Locality. — Pogibshi Island, opposite the village of Kadiak, Alaska. 
Collectors. — G. K. Gilbert, B. K. Emerson, Charles Palache. 
Helminthoida subcrassa sp. nov. 
pi. xvi, fig. 3. 
The form for which this name is proposed is represented by a 
1 Since the above was written the author has discovered two large species ap¬ 
parently of this genus, one in the Batesville Sandstone of the Lower Carbonif¬ 
erous rocks of Arkansas, the other in the somewhat younger Strawn Formation 
of Texas. This fact and the possible relations to Crossopodia are noted ante , 
page 129. 
