752 A. C. PEALE 
temporaneous in Arapahoe time, and it is stated that the affinities 
of Monoclonius are with Triceratops and that Ceratops montanus 
is the ancestor of Torosaurus, while there is a possibility that 
Monoclonius may yet be identified with Ceratops, the present 
unavoidable confusion becomes noticeably evident. 
Rearranging Lull’s table of the “Geological Sequence of the 
Ceratopsia’”* to accord with the views set forth in this paper, we 
have the following: 
Formations ss Moe Loca HESS recuse Dh att soe NDOCles is agate 
Vinicen ee sp. 
Triceratops brevicornus 
es otobs serratus 
Mance2 car. oe ee Hell Creek, Mont.. Bo 
ingequrue latus 
Trosaurus gladius 
Diceratops hatcheri 
Triceratops brevicornus 
Triceratops flabellatus 
Triceratops calicornis 
Triceratops sulcatus 
Triceratops prorsus 
Triceratops horridus 
Triceratops elatus 
Triceratops obtusus 
ances a: ike eae nese: Converse Co., Wyo....... 
Ceratops montanus 
Ceratops paucidens 
Ceratops recurvicornis 
Monoclonius sphenocerus 
Monoclonius crassus 
Wane eisesu ccs eiscrnamare Near Judith, Mont....... 
Triceratops alticornis 
PD OTEV OLS ces ceuatecooater felts Denver, Coloj awe cee Haticeratops Hormdnc 
Triceratops alticornis 
Triceratops galeus 
Ceratops montanus* 
Post-Laramie. i... cs st= Black Buttes, Wyo.......| Agathaumus sylvestris 
WEaramiensmtrcetseistoscetiee Black Buttes, Wyo.......| No Ceratopsia 
[dose] SRN boas po aden: Black Buttes, Wyo.......| No Ceratopsia 
Bierre sii) ceauetdniets nates ces Black Buttes, Wyo.......| No Ceratopsia 
ArapalO@rrc-qerate leurs cei siet Near Denver, Colo....... 
* The type specimen of Ceratops montanus is in the collection of the U.S. National Museum. As 
to the specimen from Colorado, Professor Lull thinks “‘it must be a case of mistaken identity.” This, 
in the writer’s opinion, is due to the fact that the Judith River beds and those of the Lance formation 
are mistakenly supposed to be separated by thousands of feet of beds. 
The principal differences between this table and Lull’s is the 
taking-away of the Lance formation from the Laramie; the inter- 
t Lull, op. cit., p. 184. 
