438 PROFESSOR GEIKIE ON THE 
Red of Russia, where I have myself detected them.”* If the fossils from Seat 
Craig really proved what Murcuison here contends for, they would invest that 
locality with no ordinary importance ; for from no other place in Scotland can 
paleontological evidence be adduced to show a passage from the fauna of the | 
Caithness flagstones into that of the Upper Old Red Sandstone. But a critical 
examination of the supposed proofs of a union of the two ichthyic types, leads 
to a conclusion directly opposite to that of my old chief. So faras I have been 
able to discover, not a single true Caithness flag fish has ever been found at 
Scat Craig. The Pterichthys major is common in the Upper Old Red Sandstone 
of Nairn and the Findhorn, but does not occur in Caithness. The teeth so 
common at Scat Craig (Dendrodus lamnodus, &c.) are likewise absent in Caith- | 
ness. Holoptychius and Bothriolepis are typical Upper Old Red Sandstone | 
forms. The Asterolepis, however, is a characteristic genus of the Caithness 
flags; if it could be established as a Scat Craig fossil also, a connection between 
the conglomerate of that locality and the true Caithness flags might be estab- 
lished. But I cannot learn that it has ever been found there. The A. Asmusiy, 
A. minor, and A. Malcolmsoni, are given by Acassiz as from the “ neighbourhood 
of Elgin” ; but though he was acquainted with the remains from Scat Craig, he 
does not give that locality as one of the sources of Asterolepis. The “neighbour- 
hood of Elgin ” is rather a vague description, and may include the Altyre beds on 
the one side and those of the Spey on the other. There can be no doubt, also, 
that some of the early identifications of the species,and even genera of fossil fishes 
from that region, were erroneous. Cephalaspis, for instance, was named as one 
of the fossils of the upper sandstones of Elgin.t I am disposed to believe that 
no true Asterolepis has ever been found either in the Scat Craig beds or in any 
of the upper conglomerates and sandstones of Elgin. 
Before returning from this digression, I may remark that the ichthyolites at 
Seat Craig are imbedded in a ferruginous conglomerate, and are usually more 
or less water-worn. Though there can be no doubt that these fishes, as a whole, 
really lived at or immediately before the time when the gravel was deposited 
in which their rolled bones, spines, scales, and teeth, have been preserved, it 
* Op. cit. p. 425. 
+ Matcotmsow, “Quart. Journ. Geol. Soc.” xv. p. 344. [Since this paper was read I have had an 
opportunity of examining the collection of Old Red Sandstone fishes in- the Museum of Practical 
Geology, Jermyn Strect.. In the “Catalogue of Fossils,” published in 1865, three specimens of 
aAsterolepis are marked as occurring, two of them in the Upper Old Red Saderere of the Moray Firth, j 
and one in that of the Heads of Ayal Being convinced that no Asterolepis was likely to have been 
obtained from those localities, I was gratified to find on inspection that. one of the specimens was-a 
fine plate of Pterichthys major, and that the others were Holoptychius scales—fossils eminently 
characteristic of the Upper Old Red Sandstone. My colleague’ Mr Etheridge at once acknowledged 
that. the fossils had been erroneously entered. in’ the catalogue. No doubt much of this confusion may 
be traced to the fault of the original synonymy. The Asterolepis of Eichwald and Pander is the 
Pterichthys of Agassiz; the Asterolepis of the latter naturalist is equivalent to the Homosteus of 
Asmus and Pander] 

