STRUCTURE AND AFFINITIES OF THE BRONTOTHERIDZE. 79 
tific value of the Yellowstone Park. At the same time, I am con- 
fident that I have in no degree over-estimated its value to science, 
but, on the contrary, I have been obliged to omit mention alto- 
gether of many points which might add greatly to the interest in 
this section of country, for lack of space to record them. 
If anything which I may have said shall in any way aid in de- 
veloping an interest in our park, or in any of the special depart- 
ments of science which can there be best prosecuted with success, 
I shall be well repaid for my effort. 
It must be remembered, however, that at present everything in 
this region is in a crude state, and it will be necessary to introduce 
gradually the requisite appliances for work, and means for the ac- 
commodation, transportation and sustenance of those who desire 
to work in this field. These will all come in due time, as the av- 
arice of man leads him to discover these demands for his commod- 
ities, and in the meantime we may congratulate ourselves that the 
work of destruction is stayed. 
I do not propose here to offer any suggestions nor to put for- 
ward any plans for the furtherance of scientific investigation ; my 
purpose is accomplished if I have succeeded in making a lucid 
statement of the real facts of the case. In an article to appear in 
the succeeding number of the Narurauist, it is my intention to 
enter more fully into the subject of the best methods for the 
improvement of this tract. 
ON THE STRUCTURE AND AFFINITIES OF THE 
BRONTOTHERID&.* 
PLATES I, II. 
BY PROFESSOR O. C. MARSH. 
Tue Miocene deposits on the eastern slope of the Rocky Moun- 
tains contain the remains of a group of gigantic mammals, of 
much interest, which have been named by the writer, Brontother- 
ide. Although these animals ` are less remarkable than the 
* Published in part in the Amer. Jour. of Sci., vol. vii, Jan., 1874. 
N aa 1873. 
