of the black pitchstone bedded with lytite colored and 
yellowish laminated, porphyries. Dip has changed to about 
20° south and 10 to 18°north of east® The yellow beds 
are mostly vesicular and. seoreaceous in appearance. The 
vescicles are sometimes filled with rotten spheres reaching 
1 1/2 inches in diameter. Beds are dipping at a steep 
angle until the head of the Madison is reached where they 
seem more neqrly horizontal. Hot spring formations in 
valley. Be&hler’s amphitheatre below is very like a crater 
form and. unlike other topographical features tut the 
•weathering of the cliffs which with the debris slope are 
60 to 80 feet high weather in the ordinary rough irregular 
forms. The bedding is in general apparently nearly 
horizontal but there is considerable curving. The rocks are 
the so ordinary darker obsidian porphyries. 
In continuing our course down the high side of the 
valley we came upon another crater -like amphitheatre about 
150 yards from the former. Like the former it opened out 
to the north into the river valley. It had also the curved 
wall of dark volcanic rock around the head but instead of 
being 60 yards wide by 300 long and say from 30 to 70 
feet deep 'like the former it is half a mile long opening 
out gradually below and toward the head steep and vertical, 
.having a width of 100 to 400 yards, and say in depth 200 to 
300 feet. Descend "between the two amphitheatres We soon 
reached the second and larger of the broad swampy meadows. 
The sides of the valley at the amphitheatres PLse to the 
