THE EURYPTERIDA OF NEW YORK 421 
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 asin E. scorpionis. The ocellar mound is very prom- 
inent and situated between the posterior extremities of the lateral eyes. 
The appendages, so far as seen, are like those of E. scorpionis. 
Abdomen. The tergites and sternites have the form and relative 
dimensions of those of E. scorpionis; of the postabdomen only 
one segment has been seen which indicates a tail as tubular and scorpion- 
like as in the genotype; and the telson has not been observed. The orna- 
mentation is that of E. scorpionis, 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 forma- 
tion 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 com- 
bines 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 con- 
sider this eurypterid horizon as situated at the base of the Salina beds, 
and either of Pittsford age or still older. 
Remarks. E. vaningeni is in more than one way a very puz- 
zling form. Its general features are undoubtedly like those of E. scor- 
