54 NEW YORK STATE MUSEUM 



is so nearly related to M . p r i o cl o n that some authors have regarded it 

 as but varietally different from the same. The typical European species of 

 the two Clinton forms are associated in a certain horizon of the Middle 

 Siluric, notably in Bohemia (zone of Monograptus priodon, Marr 1880, 

 with Monograptus priodon, M . vomerinus, C y r t o g r a p - 

 tus mu r c h i s o n i , R e t i o 1 i t e s geinitzianus), France (shales 

 of Feuguerolles in the Normandy, Bretagne, see Barrois, 1892), Belgium 

 (Malaise 1890), Norway (Bjorlykke) and Sweden (in Gothland). Lapworth's 

 term zone of Cyrtograptus murchisoni (zone no. 17) is generally applied 

 to this horizon in Europe. It forms in Britain the base of the Wenlock, 

 but a correlation on this basis, of the Upper Clinton shale with the lowest 

 Wenlock would be not fully warranted, since Retiolites geinitzi- 

 anus appears in various regions (Silesia, Thuringia, Bretagne) already in 

 a preceding zone which corresponds to the late Tarannon and Lapworth 

 records Retiograptus geinitzianus and varieties of Mono- 

 graptus priodon already from his zone 15 (of Monograptus exiguus 

 Nicholson). 



Another representative of the group of Monograptus priodon 

 is here described as M. priodon van chapmanensis. It occurs in 

 a brown sandstone in Aroostook county in Maine and is evidently the 

 species cited by Williams and Gregory as Mono g r a p t u s p r i d n .' 



The form from northern Greenland described by Etheridge as M n o - 

 graptus convolutus var. coppingeri would indicate the pres- 

 ence in the far North of a shale of the age of the Rastrites beds of Europe, 

 or of a horizon considerably below that of our Clinton graptolites. 



Likewise the occurrence of a variety of Climacogra p tus s c a 1 a r i s 

 in a sandstone in Maine points to the presence there of one of the earliest 

 graptolite zones of the Siluric. C . s c a 1 a r i s is a cosmopolitan form, well 

 known from the Baltic, Mediterranean — Bohemian basins and other pans 

 of the Atlantic and has also been recorded from the western Pacific basin, 



1 Bailey [1901] has also recorded the o< current e of an undetermined Monograptus in 

 several localities in New Brunswick. 



