750 A. C. PEALE 
the Judith River beds) which he says are very similar if not gen- 
erically identical, says:* 
It will be observed that five of these species [of Monoclonius and Ceratops]| 
are known to possess large nasal and small supraorbital horns. This stage 
of horn evolution may be contemporaneous and independent of that on the 
southern Laramie [Lance] dinosaurs in which the nasal horns are invariably 
smaller than the frontal horns, but coupled with the smaller size eal open 
temporal foss@ it would appear to be more primitive. 
The italics above are Osborn’s and they seem to be justified by the 
fact that we do find species of Ceratops and of Triceratops coexist- 
ing in the same beds as in the Arapahoe formation of Colorado 
which, although of post-Laramie age, is probably older than the 
Lance formation. Dr. Hay’s remarks? on the Ceratopsia are 
interesting in this connection. He says: 
Apparently nine species are known from the Judith River deposits of 
Montana and British America; and about fifteen species are credited to the 
Lance Creek beds of Wyoming, and to the Arapahoe and the Denver, of 
Colorado. Hatcher and Lull conclude that those of the Judith epoch are 
somewhat more primitive than those of the beds higher up, being somewhat 
smaller, with a less completely developed nuchal frill, with the nasal horn 
relatively larger and the supraorbital horns relatively smaller than in the 
younger forms. It is, however, to be noted that the nasal horn of Ceratops, 
of the Judith River epoch, is not yet certainly known. For the most part the 
genera are based on the characters mentioned above. They may have the 
importance assigned to them, but they do not indicate radical differences. 
Such differences might easily have arisen during an interval of moderate 
duration. 
The supposed primitive nature of the Ceratopsidae of the 
Judith River basin of Montana as compared with those of the 
Lance formation of Wyoming and the supposed stratigraphic posi- 
tions of the beds are apparently the main reliances of the advocates 
for the earlier age of the former and have led to considerable con- 
fusion in their consideration by different writers. Mr. R. 5S. Lull 
has thus been led astray in his phylogeny of the Ceratopsia, which 
is based apparently more upon supposed geological position, than 
upon the phylogenetic characters. He is evidently misled because 
Contributions to Canadian Paleontology,.III (1902), 20. 
2 Hay, op. cil., p. 24. 
3 Advance print Proc. 7th I.Z.C., Boston, 1992, Cambridge, 1910, p. 2. 
