284 Proceedings of the Royal Physical Society. 
collections, to point out specimens from Achanarras, even if 
the locality be not marked. 
And if the appearance of the fossils is characteristic, so, 
also, is the following list of species :— 
Paleospondylus Gunni, Traq. Coccosteus decipiens, Ag. 
Diplacanthus striatus, Ag. Homosteus Milleri, Traq. 
Rhadinacanthus longispinus (Ag. ). Dipterus Valenciennesti, Sedgw. and 
Mesacanthus sp, Murch. 
Cheiracanthus Murchisoni, Ag. Glyptolepis paucidens (Ag.). 
Pterichthys Milleri, Ag. Diplopterus Agassizii, Trail]. 
+ productus, Ag. Osteolepis macrolepidotus, Ag. 
9 oblongus, Ag. Cheirolepis Trailli, Ag. 
It will be seen that I have added Pterichthys productus 
and Pt. oblongus to my previous list, but the question as 
to whether these are distinct species, or only forms of 
Pt. Milleri, remains as I left it in a former communication.! 
It is certainly interesting, now to find all three occurring 
together at Achanarras, just as they do in the Moray Firth 
nodules. 
It would be going beyond the scope of the present 
paper to enter into a detailed examination of the distribu- 
tion of fossil fishes in the Caithness area; moreover, the 
subject is not yet thoroughly worked out. Nevertheless, 
a few remarks on the list given above may here be | 
hazarded. 
No such assemblage of fishes has been hitherto recorded 
from any other part of Caithness. It differs, of course, from 
the peculiar fish-fauna of John o’ Groats, where the pre- 
vailing forms are Microbrachius Dicki (C. W. Peach), Dipterus 
macropterus, Traq., and Tristichopterus alatus, Egert. Of 
other localities or districts in Caithness, the only one whose 
fossil fishes are sufficiently worked out to admit of detailed 
comparison, is the Thurso area, which occupies so much of 
the north-west, and extends southwards certainly as far 
as Halkirk. 
The following is a list of the fishes of this-area, which I 
have identified after several years careful study of specimens 
‘collected by the late Messrs Hugh Miller, John Miller 
1R. H. Traquair, On the British Species of Asterolepide—Proc. Roy. 
Phys. Soc. Edin., vol. xi., pp. 288-286, 
