35 6 FEATHERED FORMS OF OTHER DAYS. 
we find birds to be the 
rarest of all fossil re- 
mains, we pass into the 
superimposed strata of 
the mesozoic forma- 
tion, the cretaceous 
beds. Here the geologist and palaeontologist 
have been more amply rewarded for their la- 
bors — though birds still remain exceedingly 
rare in this horizon. In England the creta- 
ceous epoch has thus far yielded only a few 
scattered remains, — among others, a bird that 
seemed to bear some resemblance to a pen- 
guin, while other skeletons are far too imper- 
fect for us to learn anything very definite from 
them. In our country, from all that I can gather 
at the present writing, no remains of birds have 
yet been detected in the J urassic, but forms 
of the highest interest and value have been 
taken from the cretaceous beds of New Jersey, 
Kansas, and Colorado, chiefly by Professor 
Marsh of Yale College, who has given us in 
his magnificent work, the “ O don torn ithesj” 
elaborate and exhaustive descriptions of these 
birds. A large collection of these remains is 
now in the museum of Yale College, the first 
specimen having been taken by Professor 
Marsh in western Kansas during the winter 
of 1870. The American Jurassic fossil bird, 
which forms the exception just alluded to, is 
the Laopteryx prise its. It, too, was taken by 
Marsh, from the Jurassic beds of Wyoming, 
and so far as its discoverer has been able to 
inform us, its organization is about equally 
divided between Aves and Rcptilia. 
From the researches of this eminent pale- 
ontologist, we learn that his Odontornithes , 
or birds with teeth, formed two very dis- 
tinct types, widely separated from each other, 
though both living in the cretaceous epoch of 
this region. One of these groups contained, as 
far as we now know, small birds that were 
powerful fliers, with their teeth arranged in 
sockets, and having the joints of the spine 
biconcave, like fishes and many reptiles, differ- 
ing in this particular from any existing bird. 
The remaining group contained wingless swim- 
ming birds of large size, with their teeth in 
grooves, and has yielded the most perfect 
skeleton, upon which the genus Hcsperornis 
has been constructed. On page 356 we have 
a representation of the skeleton of this bird, 
carefully reduced by the author of the “ Odon- 
tornithes ” from his large plate. In all, Profes- 
sor Marsh has described from the cretaceous 
beds twenty species of birds, representing nine 
genera. In some of these the remains are very 
fragmentary, so much so that it would be im- 
possible to guess, with any degree of certainty, 
as to their form or affinity ; and in any event it 
would be impossible for me to attempt to de- 
scribe them all here, or en- 
deavor to say what their prob- 
able habits and forms were. So 
from them all I will choose but 
one example, Hcsperornis re- 
calls, the bird I have just men- 
tioned. Moreover, this bird has 
the double advantage of being 
the next but one in point of age 
to the ArchcROpteryx , and the 
most perfect remains of it 
have been found. The 
oldest fossil bird we 
have as yet found in 
America is Laop- 
teryx , discov- 
ered and de- 
scribed by 
RESTORATION OF THE SKELETON OF HESPF.RORNIS REGALIS. 
(AFTER PROFESSOR MARSH.) 
Professor Marsh. This bird is alluded to in 
“ Birds with Teeth,” an article not then pub- 
lished, which I was permitted to examine 
through the kindness of the author. 
In Plate 20 of Professor Marsh’s “ Odontor- 
nithes” we find a beautifully restored skeleton 
of Hesperornis , reduced to half its natural size. 
From measurements obtained from this, we 
ascertain that this strange extinct bird often 
attained a height of three feet or more. With 
this unsurpassed drawing, and aided by Pro- 
fessor Marsh’s own description as to what the 
probable appearance and habits of Hesperor- 
nis were, I have ventured upon a restoration 
of this ancient form (page 357). It is here 
represented in a position the bird must have 
often assumed, — a semi-erect attitude, with 
the body bent forward at an angle half-way 
between the horizontal and erect posture. 
He is seen to be resting for a moment after 
his exertions in his native element, for he was 
essentially a marine fowl, and is found with 
other fossil marine animals. 
