18 



FOSSIL FORESTS OF YELLOWSTONE PARK. 



nearly covered by shifting debris. Their diameter ranges from 1 to 

 4 feet, and they are so perfectly preserved that the rings of growth 

 can easily be counted. The internal structure is also in most trunks 

 nearly as perfect as when the trees were living. 



CACHE CHEEK. 



The forest that is next in size to the one a mile southeast of Junc- 

 tion Butte is on Cache Creek, about 7 miles above its mouth. It is 

 on the south bank of the creek and covers several acres. The trunks 

 are scattered from bottom to top of the slopes through a height of 

 probably 800' feet. Most of the trunks are upright, but only a few 

 project more than 2 or 3 feet above the surface. The largest one 

 observed was G feet in height and 4 feet in diameter. Most of these 

 trunks aj^pear to the naked eye to be conifers, but a number are 

 obviously dicotyledons — that is, they Avere deciduous-leaved trees. 

 The conifers, however, were the predominant element in this as in 

 the other fossil forests. 



The slopes of the Thunderer, the mountain so prominently in view 

 from Soda Butte on the south, also bear numerous fossil trunks. 

 Most of them are upright, but only a very few project more than 2 

 feet above the surface. No remarkably large trunks were observed 

 at this locality, the average diameter being perhaps less than 2 feet. 



OTHER LOCALITIES. 



Mount Norris, which is hardly to be separated from the Thun- 

 derer, also bears a small fossil forest. The trees are of about the 

 same size and character as those in the larger mountain. Fossil 

 forests of greater or less extent, composed mainly of upright trunks, 

 are exposed also on Baronett Peak, Bison Peak, Abiathar Peak, 

 Crescent Hill, and Miller Creek. In fact, there is hardly a square 

 mile of the area of the northeastern portion of the park that is 

 without its fossil forest, scattered trunks, or erratic fragments. 



The vast area east of the Yellowstone Lake and the region still 

 farther east, beyond the limits of the park, have not been thoroughly 

 explored, but enough is known to make it certain that these areas 

 contain more or less fossil Avood. The stream beds in these areas in 

 many places contain fragments of fossil Avood, Avhich indicates that 

 trunks of trees must be near at hand. 



THE PROCESS OF FOSSILIZATION. 



The manner in which these forests were fossilized may next be 

 considered. Though the Avhole history of the process is not fully 

 understood, it was undoubtedly dependent on or at least greatly 

 facilitated by the presence of volcanic and hydrothermal activity, 



