It is not clearly evident, however, that we are dealing with exactly contemporaneous assemblages when comparison is made between the Angels Peak faunule and the rest of the San Juan fauna which serves collectively to define the typical Torrejonian. It may be: (1) that the Angels Peak faunule is of slightly different age than the latter, or (2) that the latter is susceptible of stratigraphic subdivision, and the Angels Peak faunule marks one stage of a sequence in time. This problem will not be easily solved, and perhaps may never be, for concentrations similar to that of the Angels Peak faunule are of infrequent occurrence. It is beyond the scope of the present paper, and of the present stage of our knowledge of the "Torrejon" fauna, to discuss at length the possible difference in age, but the following remarks summarize the matter for the Angels Peak material. Many of the Angels Peak specimens differ in minor ways from those previously described from the Torrejonian of the San Juan Basin. Some of these differences are sufficiently great for the recognition of new species. Other differences at present are not clearly valid on a specific level, and it may become necessary to restudy the entire fauna if satisfactory conclusions ever are reached. A direct comparison can be made between the Angels Peak faunule, and a numerically smaller and less well preserved one obtained by the University of Kansas from a bone concentration near the head of Kimbetoh Arroyo. The latter faunule presumably is from the "_Deltatherium_ zone," and hence does not occupy a demonstrably high position in the "Torrejon," rather, one seemingly down toward the first known appearance of the fauna. Closely related or identical species of nine genera occur at both localities. Of these, the specimens of one species seem to be indistinguishable; the specimens of another Angels Peak member are perhaps slightly more advanced; and seven include specimens, distinguishable in greater or lesser degree, which suggest, principally in smaller size, a less advanced stage for the Angels Peak faunule. In general, the non-ferungulate part of the Angels Peak faunule seems to depart more widely from what is typical of the "Torrejon" fauna than do the Carnivora and Condylarthra. Because the former is very poorly represented in the faunule, and not too well known elsewhere in the San Juan Basin, it may be argued that the apparent differences would disappear with the acquisition of more material. This may be so, but at present the point can not be demonstrated.