172 
PALEONTOLOGY OF NEW YORK. 
Tentaculites spiculus. 
PLATE XXXI, FIGS. 21-25. 
Tentaculites spiculus. Hall. Illustrations of Devonian Fossils : Pteropoda, pi. 26, fig's. 21-25. 1876. 
Form a slender-elongate, annnlated cone; very gently expanding from the 
apex, and sometimes showing a tendency to cylindricity towards the 
aperture: annulations abruptly elevated, sometimes rounded and oblique 
to the axis of the cone; about equal to the spaces between them, and 
gradually increasing in distance towards the aperture: ten to fourteen 
annulations in the space of five mm. in specimens of the same size; 
apical portion very finely annnlated or transversely striate, about twenty 
in the length of one mm., while an equal distance measured near the 
aperture gives eleven annulations. Interannular spaces on the body of 
the shell marked by fine transverse strise, to be seen only under favorable 
conditions of the fossil. Length of longest specimens from eight to ten 
millimetres: ordinary length, four to six mm. 
This species is known almost entirely as imprints in argillaceous sand¬ 
stone, and its characters are obtained from these and from gutta-percha casts 
of the same. The extreme apical portion, in the condition in which the 
fossil usually occurs, seldom preserves evidence of annulations. 
This species resembles the T. attenuatus in many of its characters, but the 
annulations are thicker and more obtuse on the periphery, and the intermediate 
striae are fewer and stronger, as shown in a single specimen preserving the 
shell towards the outer extremity, and as apparent in the impressions of the 
exterior. This character, together with the common appearance of an obliquity 
of the annulations, are all the features that can be indicated as distinguishing 
the species from T. attenuatus, when in the ordinary condition in which the 
two forms occur. 
Formation and localities. In some semi-arenaceous layers of the Chemung 
group, a few miles south of Ithaca, N. Y., and in similar beds to the south of 
Cortland villao-e in Cortland countv, N. Y. 
