Neiu Sjyecies of Fossih from Ohio. 235 



densely filled with teeth, plates and bones of fishes, locally known 

 as the "Bone-bed." 



No. 3, about thirty feet of thin-bedded shaly limestone, the 

 "Delaware bed" of Prof. Orton. The upper part of this is 

 supposed to represent the beds of similar character at Delaware,- 

 Ohio, which contain the large fish-remains. 



'No. 4, about fifteen feet of bluish, somewhat marly shales, 

 the "Olentangy shales" of N. H. Winchell. This is followed 

 above by the Huron shales, the supposed equivalents of the 

 Genesee slates and Portage shales of New York. 



Near the lower part of No. 3, only a few feet above the 

 "Bone-bed," occurs the dark brown shale in question, with the 

 peculiar fossils, which I have no hesitation in pronouncing the 

 equivalent of the Marcellus shales of New York.. Admitting 

 this — and there certainly appears to be no alternative — the rocks 

 found, above this limit should represent the Hamilton group of 

 the New York system ; and we ought to find some fossils here, 

 characteristic of that formation, which would not pass below 

 this line. To ascertain if this was so, I requested Mr. Edward 

 Hyatt, who has collected carefully the fossils around Columbus, 

 to furnish me a list* of the species known, with their horizons 

 indicated ; and also requested the use of specimens of species 

 not known to occur below the horizon of the "Bone-bed," — 

 that being the most easily recognized limit, and the one most 

 generally studied in connection with the vertical distribution. 

 Contrary to my expectations, the species yet known not to pass 

 below the "Bone-bed " are very few. These, with the exception 

 of the Tentacidites scalar formis, have been illustrated on Plate 

 7, and are, with two exceptions, known Marcellus and Hamilton 

 types, — one being a now species, and the other {Spirffera Maia, 

 Bill.) occurring in the Upper Helderberg limestone in Canada. 

 The examination of the upper layers for characteristic fossils 

 was not carried far enough to make it i3erfect, owing to Mr. 

 Hyatt's absence from Columbus ; but the fcAV forms found above 

 these bituminous layers will readily be recognized as character- 

 istic of the Hamilton group, and warrant one in considering the 



* These lists will be found appended at the end of the present article. 



