64 Chapman, Sihirian Fossils oflSouth Yarra, &c. [ Autjusr^ 



the waters. The principal of these organisms seem to have been 

 the trilobites, pod-shrimps, bivalves, and worms ; but corals, 

 graptolites, star-fishes, brittle-stars, brachiopods, gasteropods, 

 pteropods, cephalopods, cirripedes, eurypterids, and a doubtful 

 plant are also comprised among the fossil remains. 



The majority of the fossils recorded from the Melbourne 

 division of the Victorian Silurian point to the rocks in which 

 they are found as being low in the series, a view already 

 expressed by Professors M'Coy and J- W. Gregory.* The 

 recent discovery by Mr. Spry of Ampyx supports this idea, for 

 that genus is typically Ordovician, and found only sparingly in 

 the Silurian. The graptolites and the StrejHelasma also tend to 

 strengthen this conclusion. There is, however, a peculiar and 

 marked admixture of fossils which, elsewhere, are typical of the 

 newer Silurian, as seen in the abundance of star-fishes and 

 brittle-stars, which in Great Britain occur in the Ludlow series ; 

 as well as in the striking abundance of the genus Palceoneilo, of 

 types almost peculiar to the Upper Silurian or Lower Devonian 

 of North America. On the other hand, when compared with 

 our Yeringian series, the fauna is not so consistently Wenlockian, 

 but more decidedly of an older facies. 



It may be mentioned for the advantage of collectors of fossils 

 from the Silurian mudstone of this locality that the darker blue 

 and yellow layers, being harder, yield the best-preserved 

 specimens ; for no shelly structure is retained by any of the 

 fossils, which are in the form of casts or moulds, and easily abraded. 

 In spite of this drawback, the fineness of the muddy sediment 

 has permitted the minutest detail of surface-structure to be 

 preserved ; as, for instance, in the case of the brittle-star before 

 mentioned, which shows the slender, minute spines near the 

 adambulacral ossicles quite distinctly, appearing as red iron- 

 stained casts on a yellow matrix. 



For the reason that the dark indurated mudstone t of the 

 Domain-road sewerage works may possibly belong to a slightly 

 different palaeontological zone, we have, in the subjoined list of 

 fossils, marked both localities with distinctive letters. It seems 

 more likely, however, that it is the same bed intensely indurated 

 by the numerous intersecting felsitic dykes found throughout the 

 Silurian in that area, the occurrence of which was especially 

 noted by Mr. Spry, who has kindly informed me of this and 

 many other points of interest in connection with the locality. 



My objects in bringing forward this list with notes are — first, 

 to present the collected fauna of the locality as known at the 

 present time, comprising about 67 species ; and, second, to 

 point out to our fossil collectors, actual or prospective, the possi- 



* See Gregory, J. W. ('01), p. 181. 



t This ])articular rock is often so exceedingly liard as to re>enil)le lydite or 

 hornslone. 



