144 THE CERATOPSIA. 



LOCALITY AND HORIZON. 



The type (No. 1821, Yale Museum) of the present genus and species was found by me 

 at the locality marked +2 on PI. LI. It lay in a bed of arenaceous shale, at the summit and 

 at the extreme western point of a high and rocky ridge about half a mile in length, running 

 westward from the main divide between Buck Creek and Lance Creek. At the same locality 

 I procured a considerable number of teeth of small Laramie mammals and other fossils, both 

 vertebrates and invertebrates, while at a distance of about 1 mile directly south, on. the summit 

 of a high ridge and on the opposite side of a deep canyon emptying westward into Lance Creek, 

 at the point marked ♦ 1, PL LI, and at about the same horizon, is the locality at which I first 

 discovered Laramie mammals. 



This particular mammal quarry has proved to be better than any since discovered, it alone 

 having yielded several thousand isolated teeth and jaws of these diminutive mammals. 

 Indeed, it seems almost inexhaustible, for on several occasions on which I have visited it in 

 succeeding and recent years I have always been rewarded by the discovery of a considerable 

 number of the teeth, jaws, and other remains of these animals. Usually these mammal teeth 

 have been abundant in ant hills, built by two or three colonies of ants planted at this 

 locality by me. In excavating their burrows and in collecting material from and beneath 

 the surface these tiny but industrious creatures bring together great numbers of small 

 stones with which to build the small hemispherical hillocks from 1 to 2 feet in diameter in 

 and beneath which they construct their subterranean chambers. Anywhere in this region 

 at a favorable locality among this aggregation of pebbles there will always be found a con- 

 siderable number of small fossil teeth and jaws, fish scales, small vertebrae, etc. Indeed, not 

 only do I personally, but paleontologists generally, owe a debt of no inconsiderable gratitude 

 to the aid given by the little creatures in making known the wealth of small mammals and 

 other diminutive vertebrates that inhabited this region in Laramie times. 



The horizon of the type of Sterrholophus flabellatus was perhaps somewhat above that of 

 any of the other members of the Ceratopsidae yet mentioned from this region, unless it be 

 that of Triceratops sulcatus. 



The type consisted of a nearly complete but disarticulated skull of a young individual. 

 Perhaps no other skull in all the Ceratopsia material yet discovered affords better evidence 

 as to the form and nature of the different elements. These will, therefore, be described and 

 figured in detail. 



The type (No. 1821, Yale Museum) of the present genus and species consists of the skull 

 and a considerable portion of the skeleton of a young individual. The more important of the 

 associated parts were the skull, with lower jaw, femur, ilium, and ischium, portions of the 

 scapulae, ribs, a few imperfect vertebrae, and a single ungual phalanx. 



When discovered the skull lay on its left side in a bed of loose sandy marl. The right or 

 uppermost side of the frill and the right horn core were completely weathered away, while the 

 left squamosal and parietal, together with the left horn core and the entire cranial region and 

 the left maxillary with palatine attached, lay in position and in an excellent state of preserva- 

 tion, save the horn core and a portion of the maxillary, which were extremely rotten and had 

 to be treated with a hardening solution. The right maxillary with palatine, both premaxil- 

 laries, nasals, pterygoids, quadrates, and quadratojugals, and in fact the whole anterior portion 

 of the skull, were detached and lay scattered about in the bed of soft sandy marl. Fortunately 

 they were all in a nearly perfect state of preservation. The left jugal was in position, the right 

 was detached. The disarticulated condition in which the different cranial elements were found 

 is proof of the immature age of the animal, and at the same time affords an excellent oppor- 

 tunity for determining the form and relations of the various elements of the skull. 



