REPORT OF THE DIRECTOR I919 I29 



nearest approach to the Fort Cassin fauna that I have seen outside 

 of the Champlain valley." 



The last of the Deep Kill zones that with Diplograptus dentatus 

 has probably to be excepted from this correlation with the lower 

 and middle Beekmantown (see below, p. 130). 



The shale with Nemagraptus gracilis has recently been found 

 intercalated, as Athens shale, with fossiliferous limestones in Vir- 

 ginia, by Prof. S. L, Powell, and Drs E. O. Ulrich and George W. 

 Stose.^^ Raymond, after a critical survey of the evidence furnished 

 in Virginia, considers the section as placing the Normanskill 

 definitely as post-middle Chazy and pre-Trenton and probably 

 upper Chazy age. 



The writer^'^ has in former publications correlated the last zone 

 of the Deep Kill shale that of Diplograptus dentatus, with the Chazy 

 limestone on the ground that it is separated from the preceding 

 zones by a most profound faunal change, namely, that from the 

 Axonolipa to the abruptly appearing Axonophora indicating an 

 important break between this and the preceding zone. Similarly in 

 Great Britain the zone of Diplograptus dentatus is placed above the 

 Arenig and in Sweden the middle Dicellograptus shales begin with 

 a like outburst of Axonophora, as Diplograptus, Climacograptus, 

 Glossograptus and Cryptograptus. 



This correlation of the last zone of the Deep Kill shale with the 

 Chazy seems also to be well supported by the stratigraphic nearness 

 of this Deep Kill zone to the Normanskill shale at several localities 

 in our shale belt, as notably on Mount Moreno near Hudson. The 

 descent of the Normanskill shale into line with the upper Chazy, as 

 advocated by Ulrich and Raymond, would then close the gap 

 between the Deep Kill and Normanskill zones. 



It is expected that the true position of the Rysedorph Hill con- 

 glomerate in regard to the upper Normanskill shale zone of 

 Corynoides cahcularis and succeeding graptolite shales, once clearly 

 recognized will furnish sufficient data establishing the age of these 

 shales and of those intervening between the Normanskill and Cana- 

 joharie shales. 



The intercalation of graptolite shale, carrying Corynoides 

 calicularis, Diplograptus amplexicaulis and 

 Mesograp'tus mohawkensi s in the top of the basal Trenton 



^"See S. L. Powell. Discovery of the Normanskill Graptolite Fauna in 

 the Athens Shale of Southwestern Virginia. Jour. Geol., 191S, v. 23. Percy 

 E. Raymond, op. cit., 1916, p. 234ff. 



" See R. Ruedemann, op. cit., 1902, p. 573 and op. cit., 1904, chart facing 

 p. 490 and p. 4C^. 



