66 F. H. Knowlton — Tertiary Floras of 



loides). The cotton wood (P. angustifolia) is rare, being 

 found in only one locality, according to Tweedy. Several of 

 the willows are abundant, as is also the common birch of the 

 region {Betula glandulosa)^ and the June-berry {Ainelanchier 

 ahiifolia). The other shrubs are either rare or confined to 

 few localities. 



The fossil flora, on the other hand, was especially rich in 

 deciduous-leaved vegetation. Thus the Juglandacese was rep- 

 resented by five species of Juglans and four species of Hicoria 

 (Carya), a number of which were very abundant. 



The genus Populus was particularly rich, there being no less 

 than seven species. Certain of these, as Populus speciosa^ 

 P. glandulifera^ and P. daphnogenoides, were in great abund- 

 ance, and the stratum in which they occur consists of a perfect 

 mat of these leaves. Something over one hundred examples 

 of one of these species were obtained. 



Another striking feature was the presence of numerous 

 magnificent Magnolias ; of these four species have been 

 described from the leaves and one from the thick petals of the 

 flower. One of the new species, represented by a great num- 

 ber of leaves in a flne state of preservation, appears to be more 

 closely allied to the living M. fo&tida {M. grandifolia) than 

 any previously described. 



The sycamores were also an important element in this flora. 

 Of the two species described from the leaves and one from the 

 wood, the one known as Platanus GuillelmcB was especially 

 abundant. It is found in nearly all of the Tertiary beds in the 

 Park, and is represented by nearly two hundred examples. 

 The species described from the wood is based upon a trunk 

 about one foot in diameter and is most closely allied to the 

 living P. OGcidentalis. 



Another important group is formed by four species of Aralia. 

 Of these Aralia notata was evidently the most abundant and 

 imposing plant of the whole flora. The collections con- 

 tain over one hundred specimens. I^one of them are preserved 

 entire, but there is abundant evidence to show that some of 

 these leaves must have been fully three feet in length and 

 more than two feet in width. Aralia Whitney i, a species com- 

 mon to the Auriferous Gravels of California, had striking five 

 to seven-lobed leaves often one foot in length. This species 

 was not as abundant, judging from the fossil remains, as the 

 former species, but it was apparently quite widely distributed. 

 The other species had smaller three or five-lobed leaves. 



The Lauracese was strongly represented by five genera, 

 eleven species, and a large number of examples. The genus 

 Laurus, which is now exclusively an old world form, was rep- 

 resented by six well-marked species. The genera Litsea and 



