Barbour has described only one species, Eurypterus (Anthraconectes) nebraskensis. It is represented by a large number of individuals and undoubtedly as the beds are worked over a great many more specimens will be obtained. They are for the most part in good condition, though seemingly representing only the exuviæ. The individuals are small, averaging two inches in length, the largest not being even three inches long. Barbour figures and describes, but does not name a second form which he thinks may be a species different from E. nebraskensis.
The faunal associates listed by Barbour are: "innumerable leaves, stems and fragments of certain land plants, conspicuously Neuropteris pinnules, stems of Calamites, and leaf-whorls of Asterophyllites . . . . Intimately associated with the eurypterids were considerable amounts of actual plant tissue, preserved as such since Carboniferous times." (10, 507–8).
Two species, Eurypterus ? pulicaris Salter from the Little River plant bed no. 2 of St. John, New Brunswick, and Eurypterella ornata Matthew are so doubtfully identified that Clarke and Ruedemann do not consider even their eurypterid origin as certain. (39, 93) The horizon at which they were found was originally supposed to be Devonic, but is now known to be Carbonic.
GREAT BRITAIN
Siluric. Lower Siluric Llandovery-Wenlock. The earliest eurypterid remains that have been found anywhere outside of North America, are the fragments of Pterygotus problematicus from the May Hill sandstone of upper Llandovery age, found in Eastnor Park near Ledbury, Herefordshire, England. A single chelate appendage was found associated with Nucula eastnori, Pentameri and Stricklandiniae. The Mayhill sandstone is a basal one resting by overlap upon various earlier members of the series even upon the Shineton (Dictyonema) shales at Wenlock Edge. There is everywhere a marked break and unconformity between the underlying beds and the May Hill sandstone, indicating that the latter was laid down by an advancing sea, if it was not a terrestrial (fluviatile) sandstone reworked by the sea.
In the Wenlock of the Pentland Hills, Scotland, occurs the first large eurypterid fauna of Europe. The rock containing the eurypterids is "an irregularly fissile, fine-grained sandstone, containing a
