454 



NEW YORK STATE MUSEUM 



Monograptus priodon ( Bronn) mut. chapmanensis nov. 



Plate 29, figure 2 



cf. Monograptus clintoncnsis (Hall) Dodge & Bescher. Am. Jour. Sci. 



Ser. 3. 1892. 43 .'412 f 

 Monograptus (Graptolithus clintonensis) p r i o d o n H. S. 



Williams. U. S. Geol. Sur. Bui. no. 165. 1900. p. 46 



Description. Rhalxlosome straight, of medium size (largest fragment 

 observed 60 mm long and 2.6 mm wide). Sicula not observed, sicular end 

 narrow (.4 mm), rapidly expanding (within 10 mm to 1 mm), 

 furnished with virgella. Thecae numbering 11 to 14 in 10 

 mm, normally 1 1 ; inclined at an angle of 40 , overlapping 

 from one third to one half their length ; their free portion 

 somewhat abruptly contracting to a recurving tube. Syn- 

 rhabdosome and nemacaulus not observed. 

 j'yp" s\k Position and locality. Collected by Mr Olof O. 



Nylander in a brown micaceous sandstone in the 

 northwestern part of the Chapman Plantation in 

 Aroostook county, Me. It is Miere not associated with 

 any other graptolites. 



Remarks. The preservation of this form is not 



432 



433 



434 



Fi g . 432-433 Monograp. so p er f e ct that all doubt as to its exact identification 



tus priodon mut. chap- 1 



m a n e n s i s nov. Fig. 432 111 1 Al 111 11 I ■ 1 



sicuiar end. Fig. 433 Mature would be removed. Above all the tubular distal por- 



portion of rhabdosome. Fig. 



434 Fragment of an unde- , • 1 _ 1 ' 4. „ * r iZ 1 



scribed Monograptid fmm the tions are only preserved in two specimens [see tig. 432J 



Aroostook limestone, Caribou, 



Me - and there so incompletely that the aspect ol the form 



is more that of a M . r i ccart o e ns is, with wide aperture and everted 

 denticle. In nearly all cases the rhabdosome has been fractured so obliquely 

 that the aspect reproduced in fig. 433 and which is not suggestive of a 

 M. priodon at all results. A few of the tubular portions are, however, 

 distinctly visible when the rock is placed under water. While these would 

 permit the reference of the form as well to M . p r i o d n as to M . clin- 

 tonensis, we have, on account ol the quite rapid expansion and coarser 

 form of the rhabdosome rather placed it with the former than the latter 



