15 



The Conodont, the Styliolina, and the overlying eighteen 

 inches of bituminous shale and limestone (b) may be desig- 

 nated collectively as the Styliolina band. 



The fauna of this band appeared again under more favorable condi- 

 tions during the deposition of the Naples shales, when the Goniatites 

 were much more abundant. It did not, however, reach such a luxuriant 

 development in this region, either in its first or its second appearance, 

 as was the case in the Genesee Valley. Clarke has noticed over fifty 

 species from the Styliolina band of that region, besides numerous 

 Conodonts and fish remains*. Careful exploration of these beds in the 

 region about Eighteen Mile Creek will undoubtedly reveal a richer fauna 

 than is now known, though the number of species and individuals will 

 probably always be much smaller than that characterizing the fauna in 

 the Genesee Valley. 



The Conodont limestone is seen in this section only near 

 the lower end, where the stream has cut through the Stylio- 

 lina limestone. Large blocks of the rock are scattered about 

 in the bed of the stream near the lower end of the section, 

 and for some distance below. With them are blocks of the 

 Styliolina limestone, of Corniferous limestone, and occasion- 

 ally of Encrinal limestone, these latter two having been 

 carried by floating ice from the bridge, where they were 

 brought for purposes of construction. 



Underlying the Conodont bed are about two inches ol 

 shale, which are divisible into an upper chocolate colored 

 band, frequently bearing Styliolina fissurella (Hall) and 

 occasionally Conodonts, and a lower, almost unfossililerous 

 gray band, which splits into thin laminae, with smooth 

 surfaces, having a talcose feel. Besides the Styliolina, the 

 chocolate colored slate contains numerous small, flattened 

 disclike bodies, of a black carbonaceous appearance, the 

 spores of plants allied to modern rhizocarps. These spores, 

 (macrospores) when viewed under the microscope, present 

 thick, rounded rims, and a more or less irregularly depressed 

 centre. They are frequently thickly scattered through the 

 shales, giving to them, in part at least, their bituminous 



*Am. Geol., Vol. VIII., p. 86 et seq. 



