KNowLTON.] SUMMARY. 113 



(;->) Its fossil riches, in the shape of mammalian teeth, were first 

 brought to scicntilic attention in 1861. Since that time an extensive 

 vertebrate fauna has been described by Leidy, Cope, Marsh, Wort- 

 man, Merriam, and others. 



(4) The first fossil plants were found at Bridge Creek in 1862, by 

 Prof. Thomas Condon. Since that date collections of plants have been 

 made b}^ Condon, V03 , Bendire, Merriam, Osmont, and Knowlton. 

 The plants have been studied and described by Newberry, Lesquer- 

 eux, and Knowlton. 



(.5) The fossil flora of the John Day Basin, as set forth in the pres- 

 ent paper, comprises 150 forms, distributed among 37 natural families 

 and the anomalous group of Phyllites. Of the 160 forms enumerated, 

 21 have not been named specifically, and 14 species and 1 variety are 

 described as new to science. The previously known species number 81. 



(6) The known fossil floras of the John Day Basin are all of Ter- 

 tiary age. The oldest, represented by the localities of Cherry Creek, 

 Currant Creek, and 3 miles above Clarnos Ferry, is referred to the 

 Lower Eocene. It is in the low^er part of Merriam's Clarno formation. 

 The next younger in age, exposed at Bridge Creek, li miles east of 

 Clarnos Ferry, one-half mile northeast of Fossil, and Ofiicer's ranch 

 in the Butler Basin, occupies the upper part of the Clarno formation 

 and is Upper Eocene in age. The j^oungest plant-bearing beds of the 

 region, found at Van Horn's ranch and vicinit}^, are in the basal por- 

 tion of the Mascall formation. The age is regarded as Upper Miocene. 



(7) From the facts adduced in this bulletin it is concluded that the 

 conditions which prevailed in the John Day Basin during Tertiary 

 times extended also into central Washington, northwestern Idaho, and 

 western Oregon. 



Bull. 2()4— 02 8 



