378 



BRITISH GRAPTOLITES. 



Mawr Qnarrv, near Builtli ; Hiiiltli RoaJ ; Dulas Brook, near Bniltli ; Irfon River, 

 near Builtli ; Llwynrheditli Quarry, Long Mountain; Grlyn Brook, Long Mountain, 

 etc. Ludlow District : Elton Lane ; Stormer Hall ; Elton-Lucllow Road, etc. 



Associates, etc. — Monorj. dniniis is a common fossil in almost all localities wliere 

 Wenlock and Lower Ludlow Shales are found. It seems to make its first appear- 

 ance in Britain in the zone of M. riccartonensis, and quickly becomes so abundant 

 that it is one of the commonest fossils in all the remaining four Wenlock Shale 

 zones ; it is also frequent iu the basal zones of the Lower Ludlow Shales, l)ut dies 

 out in the zone of Monog. scanicns. It may therefore occur associated with the 

 typical fossils of all these zones. 



Collections. — Sedgwick Museum, British Museum (Natural History), Hopkinson, 

 Lapworth, the Authors, etc. 



Monograptus vulgaris, Wood. Plate XXXVII, figs. 10 a — e. 



1900. Monograjjfuf! vulijarh. Wood, Quart. Joiirn. Geo]. Soc, vol. Ivi, p. 455, pi. xxv, fig. 2, aud 

 text-fio-. 10. 



Polypary 



Figs. 248 a and l. — Monograjdus vulgaris, 

 Wood. 



n 







10 cm. or more in length, stiff and straight, widening gradually 

 to a maximum breadth of 2'5 mm. Thecge 

 twelve to nine in 10 mm., those of the proximal 

 J portion relatively short and wide, while those 



of the distal portion have a length of 3 mm., 

 are four times as long as wide, and overlap 

 one-half to two-thirds their length ; average 

 inclination 35° — 40°. 

 Description. — The form of the polypary is most 

 characteristic, owing to the stiff and rigid appear- 

 ance of the proximal portion, and general absence 

 of the ventral curvature so noticeable in M. cluhius, 

 M. tumescens, and other forms. 



The sicula has a length of 2 mm., and is about 

 four times as long as wide ; it is always conspicuous 

 and reaches to the level of the second thecal aper- 

 ture. 



The early tliecie are short and broad tubes not 



(|uite twice as long as wide, and they resemble those 



, ,,. ^ , , , . . , X. of ilf, duhias : the mature thecge are, however, con- 



b. Distal end, showing virgula. hn- 



largenient of part of PL XXXVII, sidcrably longcr, being fully four times as long as 



wide. 

 Affinities. — In the length and characters of the mature thecae M. vulgaris 





['J 



■w 



a. Proximal end, showing' sieula. 

 Figured, Quart. Jovirn. Geol. Soc, 

 vol. Ivi, p. 456, fig. 10 a. Trefnant — 

 Middletown Brook, Long Mountain ; 

 Lower Ludlow Shales. Coll. Wood. 



