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NEW YORK STATE MUSEUM 



not exactly equivalent, Glossograptus quadrimucronatus, for 

 instance, appearing already in the preceding zone of Climacograptus clingani. 

 The time for exact correlation has, however, not yet arrived ; its prerequisites 

 are a more detailed zonal study of our graptolite shales, notably the Utica 

 shale, and the publication of complete fossil lists from the European 

 graptolite beds. 



The zone of Pleurograptus linearis is best developed in Scotland, where 

 it abounds in Leptograptidae, and also well known in Scania [Lap-worth, 

 1 880, Olin, 1 906]. Glossograptus quadrimucronatus is a 

 prominent form of the zone in both Britain and Scandinavia. 



The Utica shale is the first Champlainic graptolite shale which posi- 

 tively trangresses the western boundary of the Levis channel of the Appa- 

 lachian geosyncline in New York and not only 'extends the full length of 

 the Champlain basin connecting northward with the Ottawa basin, but also 

 passes in a broad belt through the Mohawk valley around and over the 

 south side of the Adirondack plateau and through the Black river basin on 

 the west side of the Adirondacks, to Lake Ontario. In Canada, according 

 to Ami [1892, p. 17], the Utica shale is first met with north of the Island of 

 Anticosti. "The Utica terrane occupies a more or less narrow and con- 

 tinuous belt along the north shore of the St Lawrence from Cape Tour- 

 mente, below Quebec, to Montreal whence the belt trends to the south, 

 . . . crossing the boundary line." An interesting outlier is found far to the 

 north of this belt in the Lake St John region or Upper Sagucnay district. 

 It is from this area that Hall's types of Glossograptus quadri- 

 mucronatus, G . ? eucharis and Leptograptus flac- 

 cid us, three of the most characteristic fossils of the Utica shale, have 

 come. 



Another outlier is found in the Ottawa basin. South of the interna- 

 tional boundary the Utica shale follows the Champlain basin appealing in 

 several small outliers on the New York side and in a broad belt o\\ the Ver- 

 mont side, especially on North Hero and Grand isle. At the upper 1 ludson 

 the belt of outcrops divides, one branch continuing southward alone; the 



