the Lower Silurian Rocks of Victoria. 5 



Genus Climacograptus, Hall. PI. III. fig. 13*. 



On a few pieces of shale accompanying Tetragraptus quadri- 

 brachiatuSj and a few other forms, are fragments probably- 

 referable to this genus. In one of these (fig. 13) the cellules 

 appear as transverse openings down the right-hand side of the 

 scalariform impression. There is likewise a faint indication of 

 the extension of the axis at the proximal end. 



Locality. Newham, near Lancefield, county of Bourke ; 

 collected by Mr. N. Taylor. 



Genus Diplograptus, M'Coy. 



Diplograptus mucronatus, Hall. PL III. figs. 14—17. 



Graptolithus mucronatus, Hall, Pal. New York, 1847, i. p. 268, t. 73. 



fig-. 1, a-d. 

 Diplograptus mucronatus, Salter, Mem. Geol. Surv. I860, iii. p. 330, 



t. 11 a. fig. 6, t. 12. fig. 1 ; M'Coy, Exhibition Essay, 1861, p. 161 ; 



Nicholson, Quart. Journ. Geol. Soc. 1S68, xxiv. p. 139. 



Prof. Nicholson recorded this characteristic Upper Llandeilo 

 Graptolite as occurring in the Skiddaw series as far back as 

 1868 5 it therefore becomes a very interesting point to find it in 

 company, in Victorian rocks, with other genera and species 

 indicative of the same beds, such, for instance, as T. quadri- 

 brachtatus, P. typus, T. brtjonoides, &c. Figs. 14 & 15 repre- 

 sent a specimen showing the distal extension of the central 

 axis and the long slender processes from the cells. In figs. 16 

 and 17 may be noticed the peculiar marginal fibres, considered 

 by Hall as giving attachment to the reproductive sacs. 

 Furthermore these fibres are more or less anastomosing, 

 forming a network similar to instances mentioned by Mr. 

 Carruthers in specimens from Moffat, and by Mr. Baily from 

 Meathf. The former remarks, " It is not easy to determine 

 how far the processes from the mouths of the hydrothecaj are 

 to be depended upon for specific characters," but would pro- 

 pose for such forms as the present, should the anastomosing 

 nature of the fibres be of sufficient importance, the specific 

 name of D. Bailyi. 



D. mucronatus is recorded from the Upper Llandeilo beds of 

 Moffat {Carruthers) , Lower Llandeilo beds of Wales (Salter), 

 Skiddaw series of the north of England (Nicholson), Hudson- 

 River group of Albany, U.S. (Hall), and has been recorded 

 by Prof. M'Coy from Victoria. 



Localities. Watchbox Ranges, near Baynton's, county of 

 Dalhousie, and Newham, near Lancefield, county of Bourke, 

 both in blue micaceous shale ; collected by Mr. N. Taylor. 



* The figure of this specimen should also be reversed. 

 t Geol. Mag. v. p. 131. 



