FOSSIL FEATHERS AND UNDESCRIBED FOSSIL BIRDS 641 
semi-plumulaceous kind. This specimen is upon a very thin 
slab, as may be observed in the figure. There is another faint 
indication of a small feather upon it, and a nondescript little 
fossil near the opposite border. It would be impossible to make a 
correct reference for this specimen or even to predict to what family 
the bird belonged that possessed it. 
Many large birds, belonging to very diverse groups, probably 
flourished at the time, and it may have belonged to almost any one 
of them, as those I have in mind would all have feathers, in certain 
parts of their plumage, something after this order. 
Among the material sent there is still another bird’s feather 
of this character from the same locality (No. 1226, Peabody Mus. 
Nat. Hist.) that I have not figured in this article. No doubt 
can exist with respect to this being a fossil bird’s feather, and one 
from a rather large bird of some species I am quite unable to 
determine—evidently one of the large wing-feathers; it shows the 
distal 70 mm. of it—the vane being, on an average, some 30 mm. 
transversely. This fossil, or perhaps its impression, is very faint 
and delicate, the surface of the matrix being almost smooth and 
flat. It will not be possible to state correctly to what kind of 
bird this feather belonged; but it may be said in passing that it 
resembles very closely the feather shown in Fig. 9. 
Another slab (No. 1230) has a somewhat faint and feathery 
fossil upon it that may represent rather large plumulaceous feathers; 
but they may not be, and I would not care to undertake to decide 
the point. On the other side of this slab there is a partially broken- 
off skeleton of a medium-sized fossil fish (No. 861)—a fact men- 
tioned merely to assist in the identification of the slab in’ the 
collection hereafter; it is from the same Green River beds of 
Wyoming, and the character of the thin slab is the same. 
Other undeterminable feathers are shown in Figs. 11 and 12 
of the present paper (d, e, and f, and da’, e’, and f’). Their museum 
numbers, the collectors, the beds and localities from whence they 
came, are, with other data, fully described in the figures throughout 
this article. In Fig. 12, I strengthened the fossils by pen and 
india-ink to give their outlines better. Nothing definite can be 
given about these as they are altogether too fragmentary and faint. 
