The Graptolites of Lancefield Beds. 169 



is pronounced. Numerous examples occur connecting these two 

 extremes, and there can be but little doubt of their identity, 

 though at first sight they seem sufficiently distinct. The 

 presence of the prolonged virgula, the much narrower thecae, 

 and their smaller angle of inclination to the axis of the bi-anch 

 sufficiently distinguish this species from T. quadribrachiatus. 



Clonograptus, Nicholson, 1873. 



Clonoraptus flexilis, J. Hall. 



(PI. XIX., Fig. 20). 



Graptolithus fiexilis, J. Hall. Geol. Surv. Canada. Rep. for 

 1857, p. 119. Id. Grap. Quebec Group, 1865, p. 103, pi. x., f. 

 3-9. Wdct. 8, p. ii. 



Hydrosome bilaterally symmetrical, copiously branching. 

 Branches of the first order in the same straight line ; those 

 of the second order diverging at an angle of about 100°; 

 those of the third order vary so much that measurements are 

 of no value, a range of from 50° to 100° having been observed. 

 Branches of a still higher order seem to diverge at a fairly 

 constant angle of between 30° and 40°, slightly curving towards 

 one another after the bifurcation. The width of the primary 

 branches is a little more than 1 mm., and from this they gradually 

 decrease in breadth till they become scarcely perceptible to the 

 unaided eye. Fairly rigid at first, they become more flexible 

 distally. Branches of the first order about 1 mm. long; of the 

 second 4 mm.; of the third about 5 mm.; of the fourth about 

 8 mm.; the distance between bifurcations of a higher order 

 increasing greatly but irregularly. Thecae not observed. 



The occurrence of this species at Lancefield has already been 

 recorded by Mr. G. B. Pritchard^ and the figure is from one of 

 his specimens, it being more distinct than any of my own. All 

 the specimens 1 have seen, about a dozen altogether, are some- 

 what stouter in their proximal parts than Hall's description 

 and plate of the Point Levis specimens indicate, in this par- 

 ticular agreeing more closely with his woodcut'^ which has been 

 reproduced by Nicholson.'* 



1 Proc. Roy. Soc. Vic, N.S. vii., 1895, p. 30. 



2 L.C.. p. 11 ; and Twentieth Report of the State Cabinet of N.Y., p. 176, f. 9. 



3 Monogr. British Grap., f. 51, p. 108. 



