Lower Siluric (Champlainic)
utica shale
Echinognathus clevelandi Walcott. Oneida county, N. Y.
frankfort shale
Schenectady and Schoharie counties, N. Y.
Eurypterus megalops nov.
E. pristinus nov.
E. ? (Dolichopterus ?) stellatus nov.
Eusarcus triangulatus nov.
E. ? longiceps nov.
Dolichopterus frankfortensis nov.
D. latifrons nov.
Hughmilleria magna nov.
Pterygotus nasutus nov.
P. prolificus nov.
Stylonurus ? limbatus nov.
Climactichnites except that in the track of Limulus the lateral and medial lines are furrows instead of ridges. Patten [Science. n.s. 1908. 28: 382] "described the movements of a modern Limulus in advancing up a sandy beach with the tide and the action of the abdominal gill plates making rhythmic ridges in the sand. He compared these with the tracks of Climactichnites which he ascribed to forms related to the eurypterids rather than the trilobites. The tracks showed a beginning in a hollow in the sand and where continued on the specimen to the further end there became fainter, as if the animal rose from the bottom. This would correspond with the habit of the Limulus, which remains buried on recession of the tide and upon its first return crawls and then swims away. Beside one track were seen two symmetrically placed impressions attributed to the longer arms of a Eurypteroid form."
In favor of this view is the fact that Strabops is a Cambric eurypterid that would appear competent to produce such tracks; but Woodworth has brought forward arguments to the effect that the trail was made by a mollusk and the sedentary impression is the end of the trail [op. cit. p. 961, 964] instead of its beginning. The direction of the obliquely transverse marks of Climactichnites is always toward the oval impressions and comparison with those of the Limulus tracks [Dawson, fig. 1-3, and also fig. 157 in Cambridge Nat. Hist. v. 4] would indicate that the animal, if an eurypterid, moved toward the sedentary impression and not away from it.
