j 4 THE CERATOPSIA 



Monoclonius sfhenocerus, type, No. 3989 A.M.N.H., consisting of nasals and left premaxillary, col- 

 lected by C. H. Sternberg, on Missouri River near Cow Island, in 1876. 



Monoclonius recurvicomis, type, No. 3999 A.M.N.H., portions of skull, including frontal and nasal 

 horn cores, discovered by Cope in 1876, on the north side of Missouri River nearly opposite the 

 mouth of Dog Creek. 



Monoclonius crassus, type, No. 3998 A.M.N.H., teeth?, sacrum, anterior dorsals, and parietal; 

 No. 3997 A.M.N.H., prefrontal and postfrontal with brow horn. Collected by Cope in 1876, 

 opposite the mouth of Dog Creek. 



Another important locality (Loc. 7, Fig. 2) is along the canyon of Hell Creek, about 30 miles 

 above the mouth of Milk River, in the northern part of Dawson County. The following specimens 

 were found here in the Lance formation: 



Triceratofs serratus, No. 970 A.M.N.H., skull, collected by Brown and Lull of the American 

 Museum party of 1902, on the extreme point of the divide separating Hell Creek from a tribu- 

 tary which entered it from the west about 1 5 miles from the Missouri River. 



Triceratofs brevicornus (?), two skulls found by W. H. Utterback of the Carnegie Museum, Pitts- 

 burgh, in 1 904, near Hell Creek. 



Triceratofs frorsus (?), skull with recurved nasal horn, collected from Hell Creek by F. B. Loomis 

 in 1929. Amherst College Collection. 



Triceratofs, No. 5033 A.M.N.H., 2 cervicals, 14 dorsals, 17 caudals, 28 ribs, pelvis and 

 sacrum, right hind limb and foot, and left femur; No. 5039, lower jaw; No. 5045, coossified 

 cervical vertebrae. These were obtained by Brown and Kaisen in 1909, 16 miles southeast 

 of Lismas. Mounted skeleton. 



Triceratofs maximus, type, No. 5040 A.M.N.H., 8 free vertebrae and 2 cervical ribs. Collected by 

 P. C. Kaisen in 1909, 20 miles south of Lismas. 



The fourth Montana locality (Loc. 8, Fig. 2) is the one referred to by Hatcher 2 on Willow 

 Creek, about 13 miles north of Musselshell postoffice. In the same paper, Hatcher also reports 

 having seen ceratopsian material on the west side of the Big Horn River, between Fort Custer and 

 Custer station (Loc. 9, Fig. 2). 



Locality 10 (Fig. 2) is in the Chalk Butte region, between Powderville and Ekalaka. Here, 

 E. S. Riggs of the Field Museum, Chicago, found a skull of Triceratofs horridus (No. 12,003), and 

 associated with it were various skeletal parts and several pairs of horn cores. These fossils were 

 included in the Lance formation. 



NORTH DAKOTA 



In the Little Missouri Badlands, in southern Billings County, A. G. Leonard collected in 

 1908, "various parts of the Cretaceous dinosaur Triceratofs, 2 or more individuals being present; 

 insufficient for specific diagnosis." The material was identified by Mr. C. W. Gilmore. It is from 

 the Lance formation (Loc. 23, Fig. 2). 



SOUTH DAKOTA 



Two localities in South Dakota have produced ceratopsian remains. Both are in the Lance 

 formation. Locality 11 (Fig. 2) is in the Short Pine Hills, Harding County, in the northeast 

 quarter of Section 35, Township 17 N., Range 1 E. It has yielded a Triceratofs skull of the 

 species horridus. The specimen is No. P 271 South Dakota State School of Mines, Rapid City. 

 From the same general locality, fragments of Triceratofs skulls have been identified by Gidley. 3 



2 Hatcher, J. B. 1896, p. 118. 



3 Gidley, J. W., 1916, U. S. Geol. Surv., Bull. 627, p. 24. 



