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" (39, 417).
Upper Siluric or Monroan. The Bertie waterlime of New York of Upper Monroan age has long been famous for the wonderful eurypterid fauna which it contains. This has been found in two localities: (1) in the quarries in North Buffalo, Erie County, and (2) in Herkimer County; there are scattered occurrences of single species in other localities, which will be referred to below. The quarries at Buffalo have yielded the largest number of remains, the specimens having been sent in great numbers to museums all over the world, and the rock has now been so well worked over that probably no new disclosures will be made. For purposes of study of the entire fauna of the Bertie the large collection in the Museum of the Buffalo Society of Natural Sciences offers excellent opportunities. The Bertie contains the largest eurypterid fauna of any one formation in the world, there being recorded fourteen species (39, 89) referred to four genera: Eurypterus (5 sp.), Pterygotus (5 sp.), Eusarcus (1 sp.), and Dolichopterus (3 sp.). The specimens are for the most part astonishingly well preserved, but other organisms are extremely rare. In the Museum above referred to are a few specimens of marine organisms obtained from the formation which furnished the eurypterids. One slab of the waterlime about 1¼ inches thick shows on one side an Orthoceras undulatum which is very much worn, the siphuncle being exposed and the surface macerated (No. 13310 E 1639 of Buf. Soc. Nat. Sci. Coll.) and on the other side is a well preserved Eurypterus head (11461 E 976). There is one other specimen of O. undulatum (13309, E 1638) of a very carbonaceous nature. There are a number of specimens of Trochoceras gebhardi, but as a rule these are found in a rock not of the character typical of the Bertie layers bearing the eurypterids. In one case it is arenaceous and not a calcilutyte (13353 E 1682), containing two fragmentary specimens. The slabs containing the Trochoceras do not have eurypterid remains on them, with one exception (13345 E 1674) in which there is a eurypterid claw on a slab showing an imperfect T. gebhardi. Associated with the eurypterids are a number of well preserved gastropod shells belonging to a genus which is also known from the Monroe formation of Michigan. This genus is Hercynella and it is represented at Buffalo by two species H. patelliformis O'Connell and H. bufaloensis O'Connell (200).
