GRAPTOLITES OF NEW YORK. PART 1 77? 



Didymograptus nicholsoni Lapworth, var. planus Elles <fe Wood 



Page 685 



10 Imperfect specimen with slightly reclined branches in the compressed state. 



Reverse side. x2 



11 Typical rhabdosome. xll 



12 Young rhabdosome. Obverse side. x2 



13 Specimen showing distinctly the origin of first theca. x2 



14 Same in natural size 



Graptolite bed 2 of the Deep kill section 



Didymograptus acutidens Lapworth 



Page 683 



15 Characteristic rhabdosome. xl-j^ 



Graptolite bed 2 of the Deep kill section 



Didymograptus cuspidatus sp. nov. 



Page 681 



16 Sole rhabdosome observed 



Ash hill quarry at Mt Moreno, Columbia co. N. Y. 



Didymograptus extensus Hall (sp.) 



Page 668 

 See pi. 14 



17, 18 Constrictiform appearance 



Graptolite bed 2 of the Deep kill section 



