GRAPTOLITES OF NEW YORK, I'ART 2 



363 



cite( 



niLii. 



the concavo-convex section and the imbricated aspect of the lateral sides. 



Gurley has then in his published lists of the North American graptolites 



amp 1 exi caul e, and in the 

 synonymy of his manuscript 

 it is brought as a synonym 

 under D. foliaceus var. 

 i n c i s 11 s. The same author 

 states in a manuscript note : 



In some specimens from 

 the Utica shale of the Mohawk 

 valley, 6 to 10 inches above 

 the Trenton limestone, D . 

 a m p 1 e x i c a u 1 e is seen ac- 

 quiring the characters of " D . 

 prist is Hall." This latter 

 form consists of a flattened 

 film. The thecal walls have 

 undergone upward deflection 

 and oblique truncation so that 

 the outline of the species is 

 characterized by the acute 

 " denticles " of the older writ- 

 ers. These denticles var)' in 

 every degree with the varying 

 condition and present an aver- 

 age type merely on account of 

 the average of conditions and 

 of polypary flexibility. 



Freeh a<i£ 



citing 



it as 



Fig. 302-7 D i p I o g r a p t u s ample 

 Portion of reverse view of rhabdosome of typical specimen, p 

 relief. Fig. 303 Impression of obverse side in limestone 



^i^ciS'U?;/" the typical form of Lapworth's 



.,.. 1 ..^ J - ... „~.~. J ~ o.uo in limestone. Fig. 304 . 



Narrow specimen showing flat reverse side preserved in relief, and im- SUbgfenUS OK" ptO°Tapt US, tei'lUS 

 pression of highly convex obverse side. The originals of figures 302 to & ./ I £> r 



it a youn 



p r i s t i s 



304 are from the Trenton limestone at Middleville, N.Y. Fig. 30s Much •. t -. 



flattened specimen showing ,k rugosus " state of preservation. From the It 2L yOUIlgeF UlUtatlOn OI LJ . 

 shale at Sandy Hill, N. Y. Fig. 396 A better preserved specimen from 



the same locality. All x 5. Fig. 307 Copy of Hall's original figures i^t r* i ^ 1" i < r,|-,.l nl^O T~T^11 



in 



the first description of the form, put cf. I), foliaceus Murchison under 



the headline, thereby indicating his belief of the possible identity of the two. 



After a comparison of large suites of this type, obtained in the Trenton 



limestone at the two above mentioned localities with the shale varieties of 



