The discovery of an early Mesozoic Fish-fauna in the Hawkeslniry- 
AVianamatta beds of New South AAMles is of considerable importance, not 
only from the stratigrapher’s point of view, hut also from tlie standpoint 
of philosophical Paleontology. Some slight information has already been 
obtained concerning the fishes of the supposed Trias and associated deposits 
of India, South Africa, and North America, as compared with the tolerably 
well-known fish-fauna of the equivalent formations in Europe ; and it is 
thus of great interest to he alile to study, in the light of known facts, 
corresponding fossils from another distant region. The scries of nearly four 
liundred specimens, nhich form tlie subject of tlie present Alemoir, were 
obtained from a layer of dark grey shale, four feet thick, intcrstratilied with 
the massive beds of sandstone belonging to the Ilawkcshury formation at 
Gosford, New South AAmles ; and though the majority of the fossils are too 
imperfectly preserved to cxhil3it many details of structure, almost all are 
capalile of precise determination. In nearly every case, the substance of 
the hones and ganoid scales has disappeared, nothing iieing distinguishahle 
except mineral -stained impressions. 
The first scientific notice of the Ilawkeshury fishes appears to he a 
brief paper by Professor J. I), Dana,* who made known a single species of 
a peculiar Palmoniscid genus, Urosthenes, from Newcastle, on tlie Hunter 
Piver ; and fifteen years later. Sir Philip de Malpas Grey Egerton t added 
further notes upon this fossil, while describing five other specimens from 
Cockatoo Island, Parsonage Hill, near Parramatta, and Chapel Hill, near 
Camphelltowu. The last-named specimens were discovered by the late Eev. 
W. B. Clarke, who forwarded two to Sir Philip, Avith photographs of the 
three others ; and these furnished one new genus and species of Palmoniscidm 
{3fyriolepis Clarkei), in addition to a supposed sjAecies of 'P ahconiscus itself 
* J. D. Dana, “Fossils of the Exploring Expedition under the command of Charles AY ilkes, U.S.X.” 
Amer. .Tourn. Sci., 1848, [2] A^ol. v, pp. 4.88, 484. 
t Sir Philip de Malpas Grey Egerton, “On some Ichthyolites from New South AVales, forwarded by the 
Piev. AV. 15. Clarke,” Quart. Journ. Geol. Soc., 18()4, Y^ol. xx, pp. 1-5, PI. i. 
