18 
THE GEOLOGIST. 
" AvES, or Birds. — JPalceornis Struthionoides, n. g. (E.). It is a re- 
markable fact that the remaijis of birds are so rare in the sandstones 
and shales in which their footprints are so common. The only frag- 
ment of a bone which has been obtained in the country, which conld 
be referred to this class of warm-blooded animals, I procured from 
the red and variegated sandstones of Anson County, N. C. It is a 
portion of the sacrum (fig. 114), natural size, and contains six verte- 
brae anchylosed together. The figure shows the under side, and 
brings to view their perfect confluence. Upon the sides these bodies 
are seen projecting laterally from the mass of bone. It is three and 
one-half inches long, one and six-tenth inches wide, and one and two- 
tenth inches thick. (See PI. IV.) 
" A microscopic examination of the bone-cells (fig. 115) confirm s 
the opinion expressed relative to the class of animals to which it be- 
longs. 1, shows the bone-cells of a fish ; 2, those of a reptile ; and 
the remaining five the cells of the bone under consideration. The 
size of this bone proves that it belonged to a large heavy bird. The 
width of the same bone in the eagle is half an inch. It is more than 
three times the size of the largest of the kind, but it is not the 
proper bird with which to compare it, for it is highly probable that 
it more resembled the Strufhiones, or ostriches, — birds with thick 
toes, — than any other living family. Its specific name has an allu- 
sion to this resemblance. The footprints of birds are mostly made by 
those which possessed toes of this description, especially those which 
are confined to the sandstone of the valley of the Connecticut." 
The first notice of bird remains in the Oolite of England was given 
in the ' Quarterly Journal of the Microscopical Society of London,' 
1857, vol. V. p. 63, in an article, illustrated with plates, " On the 
Existence of Birds during the deposition of the Stonesfield Slate, 
proved by a comparison of the Mickoscopic Structuee of certain 
Bones of that Eormation with tliose of Becent Bones. By the 
Eev. J. B. P. Dennis, E.a.S., of Bury St. Edmund's." 
Erom extensive observations made upon the bones of birds, Mr. 
Dennis found that in their microscopic characters, these bones are as 
distinct from those of mammifers as the latter are from the bones 
of saurians. " As the lacuna in the saurian bone exceeds that of the 
mammal in the size of its canaliculi, so does the latter exceed that 
of the bird ; and as they are more numerous and more branched in 
the bird than in the mammal, so, in like manner, are they more so 
in mammalian than in saurian bone." " It is in birds," he continues, 
" that the Haversian tubes attain their most elegant and varied reti- 
culations, not fortuitously, but with design, and that intimately con- 
nected with the life and habits of the animal. In fact, each bone 
is a study in itself, and involves a knowledge of the muscles that move 
it, as well as of the use it is designed for." 
The object of his paper, Mr. Dennis says, " is to prove, from a 
general exposition of the structure of birds, that they had representa- 
tives on this planet when the Stonesfield Slate was still the soft mud 
of a large estuary and for this purpose he enters (for the thorough 
