THE EURYPTERIDA OF NEW YORK 417 
105 
is also attested by telsons, some of which 
indicate a true Pterygotus [see text fig. 
106] while others suggest forms of Eret- SD 
topterus [see text fig. 107]. We also fig- 
ure with these a swimming leg, possibly pig, Scie Mrmpabats Of Pierveotidas. Big. 10s 
Swimming leg. x 2. Fig. a bbe cap ee a 
4 1 true Pterygotus. Fig. 107 Probably of an 
belonging to this group. Erettopterus. Both x 2 
EURYPTERIDS FROM THE SHAWANGUNK GRIT IN PENNSYLVANIA 
On a previous page [87] reference is made to the occurrence of obscure 
eurypterids in the Shawangunk grit of the Delaware Water Gap, Pennsy]l- 
vania. The material we then had proved indeterminable, but since then 
through the courtesy of Professor Gilbert van Ingen we have had oppor- 
tunity to examine a very large number of specimens from the same locality 
recently acquired by him and Mr J. C. Martin. In regard to the horizon 
Professor van Ingen writes: 
These eurypterids are from the third quartzitic conglomerate, ‘“‘ Medina 
white conglomerate, no. 2”’ of section B, at Delaware Water Gap, which 
is published as plate I, 1882, Report-G6 (Second Pennsylvania Geological 
Survey). They come from about the middle of this band, and occur in 
thin seams of black shale of very irregular extent horizontally and of 
variable thickness and character vertically. Some of the shale seams 
have none, others abound in the eurypterids. 
It thus appears that the occurrence of the eurypterids at the Dela- 
ware Water Gap is the same as that in the Shawangunk grit at Otisville. 
Unfortunately the maceration, already so prevalent in much of the 
eurypterid material at Otisville, has at the Delaware Water Gap reached 
such a destructive degree that the shale is filled with a mass of comminuted 
eurypterid fragments; and to complete the destruction the chitinous sub- 
stance has also been chemically altered until it has a slickensided and 
silky appearance and for the greater part has lost all trace of sculpture. 
Owing to this extremely unfavorable: condition of the material, only a 
few small carapaces and patches of integument warrant description, although 
