654 



ON THE OCCURRENCE OF MOXOGRAPTUS IN NEW 

 SOUTH WALES. 



By T. S. Hall, M.A. 



(Communicated by John Mitchell.) 



The occurrence of graptolites in the Silurian of Bowning and 

 Yass has been ah-eady recorded by Mr. John Mitchell,* but the 

 record has been since referred to as doubtful, and it is, therefore, 

 with much pleasure that I accepted Mr. Mitchell's offer to allow 

 me to examine the specimens on which the record was based. 

 They are undoubted examples of Monograptus, a genus 

 which, it is hardly necessar}^ to say, is confined to the 

 Silurian — that is, the Upper Silurian of the State 

 Geological Surveys — though unfortunatel}' the condition 

 of the specimens does not permit of specific naming. 



Monograptus sp. 



Hydrosome straight for the greater part of its length, 



slightly incurved proximally. Maximum width about 



1-7 mm.; length of a slightly imperfect specimen 12 mm. 



This is nearly the total length, as only a small part of the 



proximal end is wanting. There does not seem to be 



any distal prolongation of the virgula. The proximal 



end of the polypary is not visible in any of the four 



specimens which lie close together on the stone. The 



^^' ■ thecjie number about 10 or 11 in 1 cm., and are inclined 



to the axis at 3")°. As far as can be seen, they are about twice as 



Fig. 1. — Imperfect specimen of Monograptus, allied to M. dnhlns, Suess { x 5). 



* Proc. Linn. 8oc. N.S. Wales (2), Vol. i., 1SS6, p. 577, and (2) Vol. ill. 

 (1888-1889), p. 150. 



