FOSSIL FORESTS OF THE YELLOWSTONE. 305 



ject at different levels from the bluff and making angles with the 

 present slope. 



It is rather remarkable that only one standing stump was 

 seen with a limb in position. This is probably explained by the 

 fact that the living trees were generally covered by the volcanic 

 material to a less height than that of their lowest limb, and con- 

 sequently the upper portions of the trees were not preserved, but 

 suffered aerial decomposition. In general, the silicified tree 

 would crumble down as rapidly as the rock material surround- 

 ing it would wear away, so that only short stumps would now 

 be found, though greater lengths were petrified. The absence 

 of limbs in position is, however, mainly due to the fact first 

 named. In the cases of trees that were petrified after they had 

 fallen, both limbs and roots projecting upward were seen in 

 position. 



Specimens of rotten wood far progressed toward complete de- 

 composition were found perfectly preserved in stone. Petrifac- 

 tions of bark were of frequent occurrence, and the channeling and 

 borings of worms or insects were beautifully preserved in some 

 of the specimens, so that we literally have petrified ivormholes. 



In some of the finer water-collected debris were found beau- 

 tifully preserved impressions of leaves, showing two kinds of 

 deciduous trees, of course entirely different from any trees now 

 growing in the region. The impressions of conifer leaves and 

 the petrified part of the same wood were also found. 



These fossil tree remains are found over a wide area in the 

 park region. Along Soda Butte Creek they stand up the slope 

 from each bank, but along the Lamar River, below the mouth 

 of this creek, they exist on the left bank only, the imbedding 

 material having been entirely removed from the right bank by 

 erosion. The lowest level at which a petrified tree was seen 

 in position was on the left bank of the Yellowstone, opposite 

 the mouth of Hell-roaring Creek, at an approximate altitude of 

 6,100 feet. The highest was seen opposite the mouth of Soda 

 Butte Creek at an altitude of about 8,180 feet. These trees are 

 twelve or fifteen miles apart, and the original slope of the ground 

 between them is not known, so that they can not be taken to fix 

 the highest and lowest levels of the original forest growths in 

 this area. 



At Specimen Ridge, where the closest examination was made, 



the lowest stump seen in position was at an altitude of about 



7,000 feet, and the highest a little over 7,500 feet. There were 



here between these limiting growths certainly nine successive 



forests, and of course an equal or greater number of incursions 



of imbedding materials. 



In what has gone before I have not attempted to designate 

 Tor., xliii. — 21 



