3-40 The American Geologist. June, 1895 
tubes, each of which served as a dwelling place. He states 
that Karl Mayer had found a species of Lufravia (L. senna) 
in one of them. He also believed the tubes were bored in the 
sediment after its deposition and solidification. Heer does 
not give the fossils any name but that of "screw-stones. " 
While he was probably wrong in his interpretation of the 
specimens, it is interesting to note their remarkable resemb- 
lance to specimens of Daimoueli.r. 
Two years before this publication by Heer, Prof. James 
Hall published an interesting paper on S2)iroj)/iijfon*. The 
forms had originally been noted by Vanuxem many years 
previous, and some had been described by him as the 
"retort" and "cocktail" fucoids. Although regarded by 
him as of vegetable origin, Vanuxem did not advance any 
proof in support of the idea, and it remained for Hall to indi- 
cate a possible mode of growth. Three of his illustrations 
are here reproduced. (Plate XI, Fig. 4, a, b, c.) In his 
remarks, Hall states that the form of the fossil was that of a 
spiral frond growing upward from a small base, gradually 
expanding in its successive volutions. The axis is generally 
thickened. He says: "I have ascertained this mode of 
growth and form of the fossil by separating successive 
lamina? of the shale, and tracing the continuation of the 
same frond upward, as it appears in the enlarging discs upon 
the successive surfaces. In this manner they have been traced 
from where the diameter is less than one inch, and apparently 
near their origin; and thence through the gradually expand- 
ing volutions till they have reached the diameter of several 
inches, the spaces between the volutions being several times 
greater than the thickness of the frond. The volutions and 
the form of the disc often, and perhaps usually, continue very 
regular till the turns have reached a diameter of four or five 
inches, while the larger fronds not infrequently present irreg- 
ularities and distortions, both from unequal growth and from 
accident, evidently having been very flexible and easily dis- 
turbed." "These bodies have grown only in quiet positions, 
as proved by the fine shaly and slowly deposited matter 
*Observati()ns upon some spiriil-gTOsviujj: fucoiclal remains of the Pal- 
feozoic rocks of New York. Sixteenth Ann. llepl. Reifents Univ. of 
N. Y.. Albany, pp. 70-8:5. pi. and fif;s.. 18(i:5. 
