346 It. S. Lull— Mammals and Horned Dinosaurs. 



the exception of Quarry No. 1 and Peterson's quarry. The 

 former particularly was an immensely prolific locality and 

 there are yet at ieast eighty-five vials containing unnamed 

 specimens at Yale and more at Washington from these localities. 

 These additions have served very largely to amplify the tahle, 

 especially from Quarries Nos. 10, 9, 5, 7, and 3. 



Comparing this table with that showing the distribution of 

 ceratopsian species, it will be seen that no mammals are 

 recorded above the level of Triceratops brevicornus type, 

 so that those which were associated with the huge T. " ingens " 

 and with Torosaurus, if there were any such, are unknown. 

 Turning again to the table, the great number of species from 

 Quarry 1 must be due in part to a happy accident of preser- 

 vation ; nevertheless some species range from the level of 

 Quarry No. 1 upward, others downward, while some of the 

 commoner species like Meniscoessus robustus and M. sctolptus 

 continue throughout nearly the entire series. One rather 

 l'emarkable feature is brought out, however, in that the Tritu- 

 berculates are rarely found below the level of Peterson's quarry; 

 Quarry No. 7, which is very productive, and a lone specimen 

 in Quarry 3 constituting the record. The Multituberculates, 

 on the other hand, are as plentiful below the level of Quarry 

 No. 1 as above. This may be significant, though the greater 

 resistance to destruction offered by the more massive multituber- 

 culate molars may in part explain it. 



The material the quarry of which is unrecorded probably 

 came very largely from either Peterson's quarry or Quarry No. 

 1, if one may judge from the date of shipment as compared 

 with similar dates in Hatcher's field diary, in which the work 

 done is meagerly recorded. Quarry No. 8 I can not locate, 

 but it may be one of two unnumbered mammal localities, one 

 of which would bring it not far from the level of Beecher's 

 quarry, the other between Quarries No. 5 and No. 10. The 

 last would be more in keeping with the " tritubercnlate " 

 distribution. 



Summary 



It will be seen that the results of the above study are 

 inconclusive in some important details, which only serves to 

 emphasize the need of exact field work covering the entire 

 area. This should include a carefully prepared topographic 

 map whereupon the sections and fossil localities could be 

 plotted with great accuracy, while the paleontological task 

 should be to search minutely the whole region from south to 

 north, keeping a careful record of the exact occurrence of 

 any mammal deposits stratigraphically. There is reason to 

 believe that such exhaustive search would be rewarded by 



