382 THE FOSSILIFEROUS 
Kinnaird, it would be well that some ichthyologist had access 
to the collection, in order to determine whether in Scotland, as 
in England, we have more than one species of this singular 
genus. Dr. Fleming found in this Middle Old Red formation 
an apparent fern, with kidney-shaped leaflets; and it yielded 
several years ago, near Clockbriggs, in Forfarshire, a large spe- 
cimen of Lepidodendron, which exhibits the internal structure. 
I owe a fragment of this fossil to an intelligent geologist, Mr. 
William Miller, banker, Dundee ; but so imperfect is its state 
of preservation, that, though it presents to the microscope the 
large irregularly-polygonal cells of its genus, it bears none of 
the nicer specific marks which might serve to distinguish it 
from the several greatly more modern species which occur in 
the Coal Measures. 
Above this Middle formation lies the Upper Old Red Sand- 
stone, with its peculiar group of organisms, chiefly fishes. And 
of it, too, much remains to be known. Save that it has not 
yet produced a Coccosteus,—a genus which seems restricted 
to the oldest ichthyic group of the system,—its fishes more 
resemble those of the Lower than of the Middle Old Red. It 
has its three species of Pierichthys, its Diplopterus, and appar- 
ently its Dipterus ; and its Celacanths, chiefly of the Holopty- 
chian genus, represent not inadequately the Celacanths of the 
genera Asterolepis and Glyptolepis, which occur chiefly, though 
not exclusively, in the Lower formation. The two formations 
appear, however, to have no species in common. In looking 
over the fine collection of Mr. Patrick Duff, derived chiefly 
from the Scat Craig, in the neighborhood of Elgin, I found 
only a single ill-preserved gill-cover,— seemingly that of a 
Dipterus, — which I could not at once determine to be specifi- 
cally different from aught produced by the inferior deposit. 
Rocks of this Upper formation have not yet been detected in 
Scotland to the north of the Moray Frith ; and its richest Brit- 
