132 T1I3 DEVONIAN AND CARBONIFEROUS. Ibum..80. 





A Dumber of sections across the same series of deposits, about 50 

 miles apart, are compared. The sections are called : I Cuyahoga, II 

 Paiuesville, III Girard, IV Chautauqua, V Geuesee, VI Canandaigua, 

 VII Cayuga, VIII Tioughnioga, IX Chenango, X Unadilla, making a 

 series reaching from Cleveland, Ohio, to the Unadilla Valley, Otsego 

 County, New York. 



The individual faunas were studied in their stratigraphic order in the 

 various sections, and their relative positions in the sections were shown 

 to exhibit a shifting back and forth of the faunas during the deposition 

 of the sediments. The faunas were classified and the recurrent stages 

 of each were given names from the dominant fossils, characterizing 

 them as follows : l 



A i8 the Hamilton fauna and its immediate successors. 

 The middle Devonian fauna (A) was traced above the horizon of the Genesee 

 shale in the following successive stages: 



A 1, the Paracyclas Urata stage. 



A 2, the Spirifera Icevis stage. 



A 3, the Strophodonta mucronata stage. 



A 4, the Atrypa reticularis stage. 



A 5, the Leiorhynchus gloouliformis stage. 



A 6, the Tropidoleptus carinatus stage. 



A 7, the Spirifera mesostrialis stage. 



A 6 + is a second recurrence of the Tropidoleptus stage, found above the Che- 

 mung fauna and distinguished by the variety Owegoensis of Spirifera marcyi, 

 a characteristic variety of the granulifera type of Spiriferas. 



B is the black shale fauna, beginning in the typical or first stage of the Gen- 

 esee shale. 

 In the fauna of the black shales : 



B, the Genesee stage of Lingula spatulata. 



B 1, the second Lingula spatulata stage, in Portage shales. 



B 2, the Lingula complanata stage of the "Ithaca group." 



B 3, Lingula spatulata , third variety, in the Cleveland shale. 



B 4, Lingula complanata, second stage, in Chemung shales. 



C is the fauna of the green shales of the typical Portage group. 



C I is the Cephalopod stage, with Goniatites and large Cardiadw. 



C 2, the Lamellibranch stage, with Cardiola speciosa, etc. 



C 3 is the Portage sandstone, generally barren. 



D is the Chemung fauna associated with brown argillaceous shales, flags, or 

 calcareous sandstones. 

 The faunas of the brown shales and sandstones of the Chemung deposits were 

 classified into the following stages : 



D 1, the stage of Orthis tioga. 



D 2, the stage of Strophodonta cayuta. 



D 3, the stage of Athyris angelica, 



D 4, the stage of Bhynchonella contracta. 



D 5, the stage of Spirifera alta. 

 All of these stages, except the first (D 1) are characterized by the presence of some 

 variety of Spirifera disjuncta) =Sp. Verneuili). 



E is the fauna of the flat pebble conglomerate. 



F is the fauna and flora of the Catskill grays and reds, 

 In the Catskill rocks the fossils are very rare, but there are two stages (F 1) of the 



: 0n the classification of the Upper Devonian, by Henry Shaler Williams, Am. Ass. Adv. Sci.Proc, 

 vol. 34, 1885, pp. 225-227. 



