12 CATALOG OF FOSSIL FISHES IN THE MUSEUM 



Tully Pyrite Layer 



The Tully limestone is absent in Erie Coiyity, but on Cazenovia 

 Creek, near Springbrook, a bed of solid pyrite, 4 or 5 inches thick and 

 underlying the black Genesee shale, apparently marks the Tully 

 horizon. 



Dental plates of two species of fishes occur in this bed, both be- 

 longing to the Ptyctodontidae: Ptyctodus compressus Eastman and 

 Palaeomylus, sp. Besides these there are undetermined Pleuracan- 

 thid shark teeth, perhaps belonging to the genus Dittodus. 



Conodont Bed^ 

 (Pis. 2 and 3) 



So many of the specimens described in this catalog are from the 

 Gonodont bed, that this formation needs to be discussed in some 

 detail. The Conodont bed is a layer of limestone about four inches 

 in maximum thickness, constituting the base of the Genesee in cer- 

 tain sections on' Eighteen Mile Creek. It lies immediately below the 

 Genundewa (Styliola) limestone, and is best exposed in a few sec- 

 tions near the railroad bridge at the village of North Evans in Erie 

 County. In typical exposures^ it thins out in both directions and 

 may, therefore, be regarded as occurring in lenticular patches. The 

 name "Conodont bed" was proposed as long ago as 1879, by G. J. 

 Hinde, the designation having been suggested by the abundance of 

 Conodonts in some parts of the formation.^ 



Lithologically, the Conodont bed is an impure limestone contain- 

 ing large numbers of quartz grains, small pebbles, crinoid stems, 

 fragments of fossil wood, and other matter. Here and there are 

 fragments of pyrite and more or less broken remains of fishes and 

 invertebrates. The fishes were first recorded by Hinde, who wrote 

 concerning them as follows: 



"In addition to the Conodonts, there are in this same bed nu- 

 merous fragments of Crinoid stems, bones and plates of undetermined 

 fishes, and teeth closely resembling, if not identical with, those of 

 Ptyctodus.'"^ 



I A preliminary account of the Conodont bed fauna was presented by the authors before the 

 Paleontological Society, at the Philadelphia meeting, December, 1914. Abstract in Bull. Geol. 

 Soc. Amer., vol. 26, p. 154. 



-"One particular band of the limestone (near the village of North Evans), which I purpose 

 to designate the Conodont-bed, is filled with fragments of these small teeth." {Quart. Journ. Geol. 

 Soc, London, xxxv, 352, 1879.) 



^ Ibid., p. 3S3. Italics are ours. 



