21 



metoinis Tatei and Conocephalites cmstralis, says they are " clearly 

 of Lower Silurian age, being equivalent to the Swedish, Bohe- 

 mian, Tasmanian, and North American beds with similar fossils." 

 He refers later to the resemblance of these Trilobites to similar 

 species described by myself from Tasmania"^ and by Prof. James 

 Hall from the Potsdam sandstone of NTew York State. The Tas- 

 manian beds I had already relegated to the horizon of the Pots- 

 dam, or its British equivalent ; and the inference to be drawn 

 from Dr. "Woodward's remarks, although he simply says Lower 

 Silurian, is to the same effect. Now the Potsdam Sandstone is 

 Cambrian, and I think we may with all reason refer the Ardros- 

 san marble to the same horizon, and by induction the Kanyka 

 and Blinman beds also. 



DESCRIPTION OF THE PLATES. 

 Plate II. 



Ethmophyllum Hixdei, 67:*. nov. 



Fig. 1. Portion of a transverse section of the septal area, showing the septa 

 and the secondary deposit lining them. Wirrialpa 



2. Nearly complete transverse section of a corallum, showmg the general 



appearance and proportions of the parts, and the interseptal locitii 

 traversed by a single line of dissepiment-like divisions. Kanyka 



X 11. 



3. Imperfect transverse section, with vesicular canals of the inner lamina 



of the septal area cut across. Blimnan ... ... ... x 2. 



4. Four septa of another example highly magnified, showing the foregoing 



structure in a more marked condition. Wirrialpa. 



Protopharetra (?) ScouLARi, sj). nov. 



5. Transverse section of a small corallum, with a central vacuity as in 



Ethmophyllum, but the septal arrangement lost in a mass of dense 

 vermicular tissue. Kanyka ... ... ... ... ... x 3. 



6. Highly magnified portion of the tissue, showing a ramifying primordial 



wall (?), surrounded by a dense secondary deposit, enclosing oval, 

 oblong, or irregular spaces. 



7. Transverse section of the same individual (fig. 5) taken from a lower 



position m the corallum, with the central vacuity filled by vermicular 

 tissue, but the peripheral portion resolved into a septal area as in 

 Ethmophyllum dJi\(\. CoscmocyathiDi. Kanyka ... ... x 3. 



GiRVAXELLA, .<sp. i)ld. 



8. Portion of a section showing a number of vermiform bodies cut at 



various angles, which may be of the nature of this genus. 



"Papers and Proc. R. Soc. Tas. for 1882 (1883), p. 157. 



