GRAPTOLITES 01" NEW YORK, FART 2 27 



grap t u s whitfieldi Hall etc. This zone was first recognized by 1 1 all 

 in the Normanskill beds of the valley of the Hudson. 



In Scania, Tornquist and Tullberg have succeeded in establishing- a 

 detailed succession of zones. One of the zones of the Middle Graptolite 

 shales (zone h, of Coenograptus gracilis) contains near Fogelsong among 

 others : 



Coenograptus gracilis Hall, Lasiograptus bimucro- 

 natus Hall, D i c r an o gr ap t u s nicholsoni Hopkinson, Dicello- 

 graptus cf. sextans Hall and several species of Diplograptus and 

 Climacograptus. 



In France, Barrois [1892, p.145] has identified Diplograptus 

 f o 1 i a c e u s and D . a n g u s t i f o 1 i u s among graptolites from the sand- 

 stone of Saint-Germain-sur-Ille and tentatively referred the beds to the zone 

 of Nemagraptus gracilis. The Bohemian graptolite shales have not 

 furnished any characteristic forms of this zone. 



Lapworth's claim of the identity of the faunas of the Nemagraptus 

 gracilis zone of Great Britain and of the Normanskill shale of New York is 

 finding additional verification in the Monograph of British Graptolites 

 now being published, in which some of Hall's species not before recorded 

 from Great Britain are described ; and by the present publication in which 

 the occurrence of an additional number of forms originally described by 

 Lapworth from the corresponding British beds is recorded from New York. 

 The graptolite lists of the horizon on both sides of the Atlantic are thus 

 approaching to identity. Still, there remains a considerable number of 

 species peculiar to each of the two regions and there exist also some dis- 

 crepancies in the range of forms which call for explanation. Thus 

 Amphigraptus diverge ns Hall, which is known here only from 

 the Normanskill shale, is restricted in Great Britain to the zone of Pleuro- 

 graptus linearis, which is the second of the zones succeeding that with 

 Nemagraptus gracilis. Since it is a rather rare form in both the Normans- 

 kill zone and that of Pleurograptus linearis, it is probable that its complete 

 range is not yet known on either side. As in this instance, it would be in 

 others perhaps rash to infer migrations from slight differences — unless 



