FOSSILS AND EOCK-SPECIMENS. 595 



6. Penestella plebeia, M'Coy, 1844. 



Fenestella plebeia, M'Coy, Synop. Carb. Foss. Ireland, p. 203, 

 t. 29. fig. 3 (1844). 



Fenestella fossula, Lonsdale, Darwin's Geol. Obs. Yolc. Isl. 

 p. 166 (1844). 



fenestella fossula, Lonsd. in Strzelecki, p. 269, t. 9. fig. 1 (1845). 



Besides three well-preserved fragments of this world-wide species, 

 there are numerous indications of it in connexion with other fossils. 



Genns Peotoeetipoka, DeKoninck*, 1877. 



7. Peotoeetipoea (Fenestella) ampla, Lonsdale, 1844. 



Fenestella ampla, Lonsdale in Darwin's Vole. Isl. p. 163 (1844). 



Fenestella ampla, Lonsd. in Strzelecki, p. 268, t. 9. figs. 3a-d 

 (1845). 



There are two specimens in the Forrest collection. 



Mr. Etheridge, junior, remarks that the group is subject to great 

 variation, being very abundant in what he calls the Permo-Carbo- 

 niferous of Australia, and fining down through infinite gradations to 

 a smaller mesh. 



EXPLANATION OF PLATE XXIII. 



Fig. la. Compressed specimen of Amplexus pustulosis, n. sp., showing the 

 tubercles on the epitheca. Nat. size. 

 1 b. A smaller specimen, also compressed, having the epitheca partly 

 removed. Nat. size. 



1 c. Transverse section of a third fragment, also pressed out of shape. 



2 a. Under side of Evactinopora crucialis, sp. n. Nat. size, 

 2 b. Upper side of same specimen. Nat. size. 



2 c. Do., flank view, magnified 2^ times. 



3 a. Triracliate nucleus of Evactinopora dendroidea, sp. n. Nat. size. 

 3 b. Branch of another specimen of E. dendroidea. Nat. size. 



3 c. Portion of ditto, showing an axial section, X 2 diam. 

 3 d. Transverse section of ditto (slice on glass), x 3 diam. 



* 



Discussion. 



Prof. Boyd Daweiins pointed out the similarity of the sequence in 

 Western Australia with that long ago established as occurring in 

 Eastern Australia. 



Mr. J. C. Ceawfoed pointed out the fact that, though Carbo- 

 niferous rocks occur in West Australia, there is no coal yet known 

 there ; and referred to the difficulty of deciding as to the age of the 

 coal of Australia. 



The Atjthoe, in reply, stated that the coals of Australia appeared 

 to be of two different ages, Palaeozoic and Mesozoic. There is no 

 proof of the presence of Devonian strata in Western Australia. 



* Foss. Pal. Nouv.-Galles du Sud. pt. 3, p, 178. 



