Page:The Habitat of the Eurypterida.djvu/21

 from Eurypterus maria. A bed, said to occur between a horizon containing what is apparently a Clinton fauna (B 8x) and one containing a Rochester (or Lockport) fauna (B 19x) and numbered B 16 h, contained the following remains:
 * 1) Small carapaces, belonging to species closely related to or identical with Eurypterus maria, Hughmilleria shawangunk and Pterygotus globiceps.
 * 2) A patch of integument with finely preserved sculpture identical with that ascribed to Stylonurus sp.
 * 3) Stylonurus myops. Fragmentary, medium sized carapace.
 * 4) Coxa, probably belonging to Hughmilleria.
 * 5) Small telson of an Erettopterus.

Middle Siluric or Salinan. In the Middle Siluric of North America are several interesting occurrences of eurypterids, and the first appearance of well preserved individuals in large numbers. Specifically indeterminable fragments of Hughmilleria and carapaces of Dolichopterus (cf. D. otisius) or Hughmilleria have been found along the Pennsylvania-Maryland border in a hard black shale which is "sandy at the top and pitted by rust-stained worm-tubes" (267, 5), and which is interbedded between two sandstone members of the Keefer sandstone member of the McKenzie formation at the base of the Salina.

Of far greater interest and importance, however, are the faunas of the Pittsford and Shawangunk shales of New York and Pennsylvania. At Pittsford, Monroe County, New York, five species (or varieties) of eurypterids have been found: Eurypterus pittsfordensis Sarle, Hughmilleria socialis Sarle, H. socialis var. robusta Sarle, Pterygotus monroensis Sarle and Stylonurus (Ctenopterus) multispinosus Clarke and Ruedemann. This fauna is represented by numerous individuals, many of them well preserved, and by many fragments, but typical marine fossils are absent from the shales, although crustacea such as Emmelezoe decora and Pseudoniscus roosevelti occur. The eurypterids are here preserved in a remarkable state of perfection, the fauna being found in two thin layers of the black shales (lower one 1 foot 2 inches thick, upper one 10 inches thick) (240, 1082) and the eurypterids are in such abundance that some layers are "literally packed" with the remains. The entire fauna from these beds as reported by Sarle (240, 1081) is: Phyllocarida, 2; Synxiphosura, 1; Eurypterida, 6.

In the associated dolomitic layers were found Graptolitida, 1; Annelida (denticles), 3; Brachiopoda, 1; Pelecypoda, 1; Cephalopoda, 2; Ostracoda, 1.