R. W. Chanei/ — Flora of Payette Formation. 217 



As in the case with most of the Great Basin floras, the 

 Payette flora most closely resembles the floras from the 

 Upper Clarno and Mascall horizons of the John Day 

 Basin, with 5 species and 12 species in common, respect- 

 ively. This is dne both to the close geographic relation 

 of the two localities and to the fact that the floras from 

 the John Day Basin have been more fnlly described 

 than from any other Great Basin locality. In consider- 

 ing the age of the species common to the Payette and 

 other floras, the following summary makes the relations 

 clear : — 



Payette species occurring in the Eocene 8 



Payette species occurring in the Oligocene 5 



Payette species occurring in the Miocene 14 



Of the 8 Eocene species, 4 are restricted to the Eocene, 

 while 1 is found also in the Oligocene and 3 in the 

 Miocene. Of the 5 Oligocene species, 2 are restricted 

 to the Oligocene, while 1 is found also in the Eocene and 

 2 in the Miocene. Of the 14 Miocene species, 9 are 

 restricted to that horizon, while 3 occur also in the Eocene 

 and 2 in the Oligocene. A summary of the number of 

 Payette species which are restricted to the several 

 Tertiary systems shows : — 



Payette species found elsewhere only in the Eocene 4 



Payette species found elsewhere only in the Oligocene .... 2 

 Payette species found elsewhere only in the Miocene 9 



Several other aspects of the stratigraphic relations 

 of the Payette flora should be considered. Of the forms 

 doubtfully determined and not here listed, Ilex cf. leonis, 

 and Celastrus confluens? are Miocene species, while 

 Rhus cf. my riccE folia and Betula heteromorphaf are typi- 

 cally Eocene. Of the new species, a species of Prunus 

 may be related to two species of the same genus from the 

 Mascall, and species of Betula, Acer, and Quercus find 

 their closest relation to living species. Of still greater 

 importance is the bearing on the problem of a flora 

 recently collected at Austin, Oregon, which appears to 

 be certainly from the Mascall formation of Miocene age. 

 In this flora, associated with typical Mascall species, 

 are Quercus consimilis, Quercus clarnensis, and Ulmus 

 speciosa, all of which are typical Upper Clarno species. 



