KNOWLTON.] PLANTS OP THE PAYETTE FORMATION. 735 



resemblance that it has been thought best to describe them under 

 this name. A more obvious affinity will be accepted if pointed out. 

 For geological purposes this species will serve admirably. 

 Locality: Idaho City, Idaho. 



PHYLLITES FLEXUOSUS n. sp. 

 PL Oil, fig. 8. 



Leaf membranaceous, outline probably broadly lanceolate; base 

 and apex destroyed ; margin undulate-toothed ; midrib strong, straight ; 

 secondaries many pairs, alternate, straight or oftener very flexuose, 

 camptodrome or subcraspedodrome, entering the obscure blunt teeth; 

 finer nervation not retained. 



This is only a fragment, and perhaps should not be given a name, 

 but it appears to be quite characteristic, and hence has been given 

 this preliminary name pending the discovery of more perfect material. 

 The width is about 6.5 cni . 



No attempt has been made to search for affinities, as it is too frag- 

 mentary to afford satisfactory diagnostic characters for comparison. 



Locality: Two miles southeast of Marsh post-office, Boise County, 

 Idaho. 



PHYLLITES OBSCURUS n. sp. 

 PI. XCIX, figs. 10, 11. 



Leaves small, elongated-elliptical, with entire margins; petiole 

 long, thick; midrib thick, straight; other nervation not preserved. 



The two little leaves figured are all that were contained in the 

 present collection. The smaller is 2 cm in length, and about 6 mm wide. 

 The petiole is about 4 mm in length. The larger leaf was about 3.5 om 

 in length and about 8 mm in width. The petiole is about 8 mm in 

 length. 



As the nervation is not preserved, it is impossible to refer these 

 leaves to a known genus with any degree of certainty. They are 

 consequently not of great importance. 



Locality: Two miles southeast of Marsh post-office, Boise County, 

 Idaho. ' 



DISCUSSION OF THE FLORA AND ITS BEARING ON THE 

 AGE OF THE BEDS. 



As here enumerated, the flora of the Payette formation embraces 32 

 forms. Of this number, 17 are described as new, while 5 are not spe- 

 cifically named, thus leaving only 10 species, or nearly 33 per cent, 



