226 MEMOIRS OF THE CARNEGIE MUSEUM. 
just north of the White River, Nebraska, and east of Andrews, our point of shipment this summer. 
I do not know just how the trail would run, possibly Mr. Peterson does, but it would seem to cross 
the Niobrara not far from the Agate Spring Quarries if one may judge from the map. 
“While Clifford’s collection had been made before leaving Crow Buttes, it was not boxed 
until he reached Sydney, so that any material picked up en route could readily have been added. 
“All this evidence seems to be in accordance with Peterson’s belief as to the probable locality 
of the type of Moropus. I should however like to learn your judgment in the matter.” 
Inquiry has developed the fact beyond doubt that the military road between 
the Red Cloud Agency and Sydney, over which in 1875 travel between the Union 
Pacific Railroad and the Fort on the White River took place, crossed the Niobrara 
River on the property locally known as ‘‘ Lower 33,” this being the name of a 
horse-ranch. The point where the crossing was made, is, as I am informed by 
those who are familiar with the country, east of the ranch now owned by Mr. 
Octave Harris, and therefore between four and five miles east of the Agate Spring 
Quarries. Exposures of the lower Harrison beds containing fossils occur all along 
the Niobrara River for a considerable distance eastward from the point where the 
collections of the Carnegie Museum have been made, possibly for twenty miles, 
though the exact eastern limits of the outcrop of these beds have not as yet been 
definitely ascertained. It is thus definitely ascertained that the types of Professor 
Marsh were collected by Mr. Clifford at the time he was in the neighborhood of the 
crossing of the Niobrara River while on his way from the Red Cloud agency to 
Sydney. They may possibly have been picked up by him at the identical spot 
where the work done by the Carnegie Museum has been carried on; or they 
may have been surface fragments coming from the same beds which he found 
at some point east of the locality which was explored by Mr. Peterson 
and his associates. Without any further evidence than that which we possess 
it is of course impossible to locate the exact spot at which the remains were 
recovered, but that they came from the Lower Harrison beds on the Niobrara 
River is in the opinion of the writer established beyond the shadow of a doubt. 
In view of this fact, inasmuch as there is absolute agreement between the skull 
collected by Professor Barbour and the skull in the possession of the Carnegie 
Museum so far as dentition and all other important points, even that of size, are 
concerned, the writer is compelled, though reluctantly, to regard the name Moropus 
cooki, which Professor Barbour has proposed for the specimen, as a synonym for 
Moropus elatus Marsh. 
5. Moropus petersoni Holland, Science (New Series), Vol. XXVIII, p. 810 (Dee. 6, 
1908). 
