New South Wales . 
4i 
Coal Measures arc horizontal or inclined they merely follow the 
same condition in the Upper or Lower Marine heds with which 
they are always associated. 
The argument from the occurrence of fish remains is met by 
the incidental remark that the “ heterocercal ganoid fishes being 
of genera and species 'peculiar to the locality have no value” in 
determining the age of the beds in which they occur, may be 
met by the retort that if peculiarity is to bo a guide in deter¬ 
mining geological age, there is an end of any certainty for such 
persons as affect to uphold their own theories by reference to 
peculiar plants; and this Professor M‘Coy himself does in rela¬ 
tion to a Scarborough plant by which he affects to guide his 
Oolitic determination to the exclusion of Glossopteris and its 
usual associates. 
Respecting Paheoniscus, one of the New South Wales fishes, a 
passage translated from Agassiz, whose decision ought to be 
satisfactory, will not he out of place, considering that it meets 
the objection on the form of the caudal fin. Ho says,—“I know 
ten species of this genus, which appear to he limited to Coal 
Measures and the Zechstein. It might not. however, be impossible 
to discover traces in the Ores Inyarre ,* the Mnschelkalk, and the 
Keuper ” (/.<?., in the Trias); “ but that which I believe I am able 
to affirm is, that it docs not ascend to the Jurassic formations, of 
which the numerous representatives of the order of ganoids have 
the tail regular , and never prolonged in a long point forming the 
upper lobe of the caudal, as takes place constantly in the genera 
of the earlier formations. I do not understand what were the 
intentions of Nature which have produced these singular 
differences, but it is certain that they exist, and it would be to 
misunderstand our duty to ignore them, or to attribute less im¬ 
portance to so general and constant a fact.” (“ Recherchcs sur les 
Poissons Fossilcsf tom. 1, p. 43.) To this may be added, that the 
generality of the fishes in N. S. Wales are heterocercal; 
* lie afterwards names P. catopterus as belonging to this sandstone. It 
was, however, only found in one spot, only “ a few square feet” in extent, in 
the county of Tyrone : ( PortlocJc : “Geology of Londonderry, Tyrone, and Fer¬ 
managh, p. 4G8.”) Respecting this fish, Dr. Traquair says (Q.J.G.S. xxxiii, 
p. 565, op. cit.) — “ Tin's little species from the Triassie red sandstone of 
Rhone Hill, county of Tyrone, was originally named by Agassiz, hut was not 
described by him. Sir C. Lyell, however, in referring to it in connection with 
certain American Triassie forms, says, concerning it, — ‘The Irish Paheoniscus 
catopterus of Roan or Rhone Hill, referred by Col. Portlock to the Trias, is 
a true l’alteoniscus. and not allied gcnerically either to the Ischypterus of 
Egerton, or the Catopterus of Rcdfield (Q,J.G.S„ iii> p. 278) ; and in Sir 
P. Grcy-Egerton’s brief description of the species (Q.J.G.S., vL, p. 4) occurs 
the following passage,—‘ The dorsal fin is placed much nearer the tail than 
in any other species ; in this respect, hut in no other, P. catopterus resembles 
the genus Catopterus of Mr. Reclfield. The tail is decidedly licterocerquc 
