Victorian Fossils, Part XVIII. 169 



Another locality in Victoria for /'. crossleii is on a branch of the 



Saltwater River, one mile west of Gisborne. Tt is interesting to 

 note that the rock in which this specimen occurs bears a strong 

 resemblance to the Keilor graptolite-bearing mudstones, tin' latter 

 series showing relationships in- regard to the trilobitic and grapto- 

 litie contents, to the Newer Silurian scries. 1 This specimen, except 

 for a certain amount of crushing, is fairly complete, and its essen- 

 tial characters are easily seen; it occurs in olive grey mudstone. 

 The only other trilobite with which it could be compared is P. 

 serratus, Foerste, which also is a Yeringian form in Victoria. 



In the museum collection there is a fine specimen of P. cross- 

 leii, from Kinglake West, measuring 44 mm. in length. The rock 

 in which this occurs is a black indurated mudstone, and contains 

 several Yeringian fossils, among which are Pleurodictyum mer/as- 

 tomum and Dalmanites meridianus . The granulate thorax and 

 absence of dorsal spines place it with the species P. crossleii. 



Horizon and Occurrence. — Silurian (Yeringian). Ruddock's 

 quarry, near Lilydale; collected by Mr. R. H. Annear. 



Also from Kinglake West; presented by Mr. Allan M. Savage. 



Also Silurian (probably Yeringian), from a branch of the Salt- 

 water River, one mile west of Ph'shorne ; coll. bv Geol. Surv. Vict. 



Phacops serratus, Foerste. (Plate XV., Fig. 16). 



Phacops serratus, Foerste, 1888, Bull. Sci. Lab. Denison Univ., 

 vol. III., p. 126, pi. XIII., fig. I. Etheridge, jnr., and Mitchell, 

 1896, Proc. Linn. Soc. N.S.Wales, vol. X., 2nd ser., p. 495, pi. 

 XXXIX., figs. 7, 8; pi. XL., figs. 7, 8, 11. 



Observatio?is. — Etheridge and Mitchell point out the rather close 

 relationship which this species bears to P. crossleii. I have found 

 the Victorian examples of P. serratus considerably smaller than P. 

 crossleii, and this, with its feebler granulation on the thorax and 

 the development of the spiny or angular axis, serve to show that 

 there is a distinction, which, as Etheridge and Mitchell observe, 

 may be only a sexual one. 



The larger of the two Victorian specimens of P. serratus has a 

 length of 21 mm. 



Horizon and Occurrence. — Silurian (Yeringian). One and a-half 

 miles below Simmond's Bridge Hut, on the Yarra. Coll. Geol. Surv. 

 Vict, (B16). 



1 See Chapman, Pal. Sil. Vict. Rep. Austr. Assoc. Adv. Sci., Melbourne meeting, 1913, p. 210, 

 and lists of fossils. 



