No.l.] HOLMES ON FOSSIL FORESTS OF YELLOWSTONE PARK. 129 



Laurus canariensiSy 

 Tilia (new sp.), 

 Fraxinus (new sp.), 

 Diospyros (new sp.), 

 Cornus (new sp.), 

 Pteris (new sp.), 

 Almis (new sp.), and a 

 Fern (new sp.). 



It will be observed tliat most of these species are new, which was also 

 the case with the collection of Professor AVhitney. 'it is also worthy of 

 remark that none of the genera are identical with those of t\ie Elk 

 Creek locality previonsly mentioned. The stratigraphical relations of 

 the two localities cannot easily be made ont, as they are separated by 

 fifteen miles of broken coimtry in which the strata are obscured by igne- 

 ous flows and Quaternary drift. The Elk Creek strata are lower by fully 

 one thousand feet. 



As far above the leaf-bearing horizon as I was able to ascend, the sili- 

 cified trunks were very numerous and well preserved, and, by the aid of 

 a field-glass, others could be detected in aU i^arts of the chit" to the 

 highest stratum. 



At another point, nearly a mile farther east, I climbed the rugged 

 walls of the mountain for the purpose of examining a number of large 

 trees that were visible from below. Trunks and fragments of trunks 

 were found in great numbers and in all conceivable positions. In most 

 cases the woody structure is well preserved, the trunks have a tendency 

 to break in sections, and on the exposed ends the lines of growth, from 

 center to circumference, can be counted with ease. In many cases the 

 wood is quite completely opalized or agatized, and such cavities as ex- 

 isted in the decayed trunks are filled with beautiful crystals of quartz 

 and calcite. Our party was so fortunate as to procure some very hand- 

 some specimens of amethyst and ferruginous quartz. It is a matter 

 worthy of observation that nearly aU of the beautiful crystals that occur 

 so plentifully in this region have been formed in the hollows of silicified 

 trees. The same fact has been noticed in regard to similar crystals in 

 many parts of the West, and notably in the case of the smoky quartz of 

 the Pike's Peak region in Colorado. 



The silicifying agents have been so unusually active in the strata of 

 the Volcanic Tertiary that not only are all organic remains thoroughly 

 siHcified, but all cavities in the loosely bedded rocks and all fracture- 

 lines in the strata are filled with chalcedony or other forms of quartz. 



On reaching the heavily bedded conglomerates of the up]ier third of 

 the cliff, I found the trees still more perfectly preserved. Many of the 

 trunks are twenty and thirty feet in height. Their roots are in most 

 cases imbedded in the layers of finer-grained materials, in which they 

 grew, while the battered and branchless trunks are encased in the coarse 

 conglomerates and breccias. These latter rocks are composed chiefly of 

 BuU. V, 1 9 



