322 i?. S. Lull — Mammals and Homed Dinosaurs. 



established themselves, but where mammals are found to be fairly- 

 abundant, it is well to bring a few shovels full of sand with ants 

 from other ant hills which are sure to be found in the vicinity, 

 and plant them on the mammal locality. They will at once 

 establish new colonies, and, if visited in succeeding years, will be 

 found to have done efficient service in collecting mammal teeth 

 and other small fossils, together with small gravels, all used in 

 the construction of their future homes." 



Thus it was that the bulk of the Yale collection was secured. 

 At first the collecting seems to have been done somewhat at 

 random, or at any rate no record of exact locality is noted with 

 the various specimens. Later, however, each specimen bore a 

 quarry number, so that not only can its exact geographical 

 origin be determined, but the stratigraphic level may also be 

 learned with a considerable degree of accuracy. 



This material speedily began to find its way to New Haven, 

 especially while Beecher was in the party, as Professor Marsh's 

 comments show, and with his characteristic energy when once 

 his interest was aroused, the latter at once began the publica- 

 tion of the descriptions and figures of these remarkable forms. 



Descriptions by Professor Marsh 



The first of these descriptive papers appeared in this Jour- 

 nal for July, 1889, in which he described seventeen species 

 representing no fewer than twelve distinct genera. August of 

 the same year saw the publication of the second part of the 

 paper, and the third appeared in March, 1892, bringing the 

 total number of species up to thirty-two, while of genera there 

 were eighteen in all. These publications also include a discus- 

 sion of relationships and family definitions and were but the 

 projected beginning of an extensive monograph upon the group, 

 the completion of which was prevented by the distinguished 

 author's untimely death. Aside from a quarto publication by 

 Professor Osborn, reprinted in part in his " Evolution of mam- 

 malian molar teeth," little has been done on the Lance mam- 

 mals by other writers, and practically every genus and species 

 known is contained in the original series described by Pro- 

 fessor Marsh and based upon types preserved in the Yale 

 collection. 



Summary of the Lance fauna 



The Lance formation has produced an extensive vertebrate 

 fauna of which the dinosaurian element is by far the most con- 

 spicuous, consisting as it does of the terminal representatives 

 of all the phyla except the long extinct Sauropoda. There 

 were also turtles and crocodiles, lacertilians and champsosaurs, 

 and a number of genera and species of tiny mammals. 



The mammalian forms are included uuder at least two of 



