1176 ON SOME ADDITIONAL LABYRINTHODONT FOSSILS, N. S. WALES, 



in process of construction between the Great Northern and 

 Sydney, at a point near Gosford, a well-known village on Brisbane 

 "Water, the northern arm of Broken Bay. Together with it were 

 found large numbers of Cleithrolejns, Palceoniscus, and many other 

 ganoids as yet undetermined. 



The Matrix of these specimens is a light grey micaceous shale, 

 belonging to one of those beds of similar character which are 

 frequently intercalated in the Upper Hawkesbury rocks. This 

 particular piece contains fragmentary plant impressions, of ferns and 

 Phyllotheca, a nearly perfect specimen of Cl&ithrolepis, the body 

 and tail of a Palceoniscus (both of them species well-known as 

 belonging to the Wianamatta formation in N.S.W.), and above all 

 the interesting stranger now for the first time introduced 

 to our acquaintance. This fossil exhibits, as I shall afterwards 

 point out in detail, the head, the shape of which may be compared 

 to that of Platycephalus, the throat- or thoracic- plates, and the 

 vertebrae and ribs of the trunk. The tail is broken off by the 

 unfortunate fracture of the stone. 



The Head has the upper surface exposed, and is parabolic in 

 outline, rather squarely convex to the rear, displaying large oval 

 orbits, a parietal foramen, and (probably) one nostril ; it is covered 

 with bony plates, which are obscurely sculptured in very faint relief. 



The Thoracic plates are whitish or chalky in appearance, owing 

 to the presence of calcite in their radiating furrows. They look 

 as if they belonged to the upper and not to the lower surface 

 of the animal. But they correspond so exactly with all that is 

 recorded as to the Thoracic plates of the Labyrinthodonts (Miall, 

 Report Brit. Ass. 1873, p. 241 ; Owen, Palaeontology, p. 179 ; 

 Lydekker, Palaeontologia Indica, Ser. IV. Vol. I. &c, &c.) 

 that one must regard them as belonging to the ventral face, 

 for on close examination it may be seen clearly that the medial 

 shield overlaps the inward margins of the laterals ; whereas, 

 as seen from the outside, "it is overlapped by the lateral plates to 

 a considerable extent, especially upon the antero-external borders ; 

 and frequently only the hinder part is exposed," (Miall, I.e.) and 



