Schuchert [1904] is of the opinion that, judging from the associated brachiopods, the Kokomo cement beds are probably of Noblesville, i.e. essentially Lockport age, and surely not of the age of the Bertie waterlime of New York, since no beds younger than the Guelph are known from northern Indiana. The aspect of the Kokomo fauna is in full accordance with this correlation since at least two of the species (Onychopterus kokomoensis and Drepanopterus longicaudatus) may be considered as older types than the species of the Bertie waterlime and following faunas.
The Guelph dolomite, like the Clinton, has afforded only a single straggler, the eurypterid facies of the horizon not yet having been observed; but the directly following age, that of the basal Salina, is represented by two faunas in New York State, viz, those of the Pittsford and Shawangunk shales. While these two have no species in common, they are characterized as probably belonging to approximate horizons by the presence of the genus Hughmilleria in both and by the similarity of their sedimentary and faunal aspects in general.
The Pittsford Eurypterus bed has been found by Sarle to be but 20 feet from the base of the Salina group; while the Shawangunk grit rests unconformably on the upturned edges of the Lower Siluric shale and, before the discovery of its eurypterid fauna, had been referred to the Salina by Hartnagel [1903, p. 1175; 1907, p. 50] on purely stratigraphical evidence, the latter consisting in the fact that the Shawangunk grit is conformably overlain by a series of formations of upper Salina age.
The Pittsford shale is separated by the main body of the Salina formation (Vernon and Camillus shales) from the principal eurypterid-bearing horizon of the State, the Bertie waterlime. In the exposures of the latter about Jerusalem hill in Herkimer county and in the quarries at Buffalo it has afforded the fauna described by Hall in the Palaeontology of New York and later exploited by Grote, Pitt and Pohlman. It is a fauna in which the genera Eurypterus and Pterygotus prevail in number of species (Eurypterus with five, Pterygotus with three) and in the size of the creatures,
