Page:The Eurypterida of New York Volume 1.pdf/429

 anterior margins are furnished with a filiform border, the posterior with a narrow doublure. The carapace culminates between or just posteriorly of the lateral eyes, a broad ridge extending thence backward toward the posterior margin. The lateral eyes were relatively small, only about one seventh the length of the carapace, submarginal, situated just posteriorly of the base of the tonguelike anterior process, apart about their length and about half their length distant from the lateral margin. The visual surface is as in. The ocellar mound is very prominent and situated between the posterior extremities of the lateral eyes.

The appendages, so far as seen, are like those of.

Abdomen. The tergites and sternites have the form and relative dimensions of those of ; of the postabdomen only one segment has been seen which indicates a tail as tubular and scorpionlike as in the genotype; and the telson has not been observed. The ornamentation is that of, but the scales are smaller and more closely arranged.

Horizon and locality. The concretionary block which contained the remains of the three specimens was found loose at the foot of a high bank of Salina beds in Oriskany creek, near Farmers Mills, 3 miles south of Clinton, N. Y. The block is also full of lingulas and orbiculoideas by means of which its horizon in the bluff could be determined. It is there located about 21 feet below the base of the red Vernon shale in dark gray shales with intercalated waterlimes and dolomite beds. This shale formation has been considered by Mr Hartnagel as equivalent to the Pittsford shale, the lowest formation of the Salina beds in New York; or, as it combines the dark gray Pittsford shale with the typical Lockport dolomite, as the interlocking boundary of the Niagaran and Cayugan groups, or the closing stages of the Niagaran. However that may be, it is safe to consider this eurypterid horizon as situated at the base of the Salina beds, and either of Pittsford age or still older.

Remarks.  is in more than one way a very puzzling form. Its general features are undoubtedly like those of