R. 8. Lull — Mammals and Homed Dinosaurs. 321 



material might be found, but success in this regard is still short 

 of fulfillment. 



Historical Resume, 



To John Bell Hatcher belongs the honor of discovering, not 

 only the rich mammalian locality under discussion, but, with 

 the exception of a premolar tooth, an imperfect molar and the 

 distal end of a humerus found by Dr. J. S. Wortmann in 

 Dakota and described by Cope in 1882 as Meniscoessus con- 

 quistus, the Cretaceous mammals themselves. In 1888, Mr. 

 Hatcher, then an aid to Professor Marsh, searched for mam- 

 mals in the so-called Laramie formation in Montana and South 

 Dakota, but without success. The following year, however, 

 lie went into what was then Converse County, Wyoming, in 

 pursuit of horned dinosaurs', the discovery of which had been 

 made known to him the year previous, and the results of the 

 next few years (1889-1892) not only brought to light the 

 remarkable series of more than thirty skulls and skeletons of 

 these and other dinosaurs, but several thousand isolated teeth, 

 jaws, and bones of mammals. To Hatcher, therefore, belongs 

 the major credit for the discovery of this material, but he was 

 ably seconded by Messrs. Peterson, Utterback, and Sullins. 

 Peterson's work was especially valuable if one may judge from 

 the held and museum records, for " Peterson's Quarry" is one 

 of the most productive localities of all. 



Although Hatcher does not mention it, Professor Charles E. 

 Beecher of Yale was a member of Hatcher's party during the 

 summer of 1889 and the following spring (1890) and did a 

 large part of the actual work on the mammals. 



Hatcher (1896, p. 119) thus describes the method of field 

 xesearch : 



"The small mammals are pretty generally distributed but are 

 never abundant, and on account of their small size are seen with 

 difficulty. They will be most frequently found in what ai-e 

 locally known as ' blow outs ' and are almost always associated 

 with garpike scales and teeth, and teeth and bones of other fisb, 

 crocodiles, lizards and small dinosaurs. These remains are fre- 

 quently so abundant in 'blow outs ' as to easily attract attention, 

 and when such a place is found careful search will almost always 

 be rewarded by the discovery of a few jaws and teeth of mam- 

 mals. In such places the ant hills, which in this region are quite 

 numerous, should be carefully inspected as they will almost always 

 yield a goodly number of mammal teeth. It is well to ... . 

 sift the sand contained in these ant hills, thus freeing it of the 

 finer materials and subjecting the coarser material remaining in 

 the sieve to a thorough inspection for mammals. By this method 

 the writer has frequently secured from 200 to 300 teeth and jaws 

 from one ant hill. In localities where these ants have not yet 



