The Mountaineer 9 
The lava eruptions from Adams have been independent of 
the great basalt flows which characterize the country to the 
eastward. The latter have come up through great fissures 
rather than through tubes or other circular openings. Such a 
method of origin gives rise to great sheets which are piled 
horizontally one upon another. This horizontal position is al- 
ways retained unless subsequently the sheets are arched and 
folded in the general process of mountain building. 
Ever since the first explorers traversed the upper White 
Salmon valley, the lava cones about Trout Lake and Guler 
have been known. They oceur for several miles lengthwise 
of the valley and some have been produced in one of the later 
lava flows which has come from the south side of the great 
mountain. The highways pass above them and the traveler is 
made aware of their presence beneath him by the deep rumbling 
sound which arises when a vehicle passes over their roofs. The 
roofs are sometimes arched and slightly broken so that en- 
trances may be effected into the caves beneath. One of the 
best known eaves is located 114 miles southwest of Guler. An 
entrance to the cave is easily possible through a hole in the 
roof at one point, and the descent to the floor made by means 
of a ladder. It is the custom to make torches of sticks of pine, 
filled with pitch, and bound together with wire. Such torches 
hght up the cave sufficiently to see its size, shape, and other 
characteristics. It is about 34 of a mile in length, from 30 to 
40 feet in width, and measures about the same from floor to 
roof. The floor is fairly level, except where large blocks of 
rock have fallen down from the roof; the sides are sometimes 
perpendicular, but usually lean outward somewhat from the 
center; the roof has a low arch, sometimes almost flat. The 
lava of the floor is ropy, Jagged, and rough and shows strong 
evidences of its once molten character. The lava of the sides is 
smoother and shows usually a curious ribbed effect like the sur- 
face of a wash-board. 
From the analogy with the occurrence of lava caves else- 
where, it seems that the last sheet of lava flowed over a land 
surface that was very uneven and broken. It was doubtless 
roughened by many small stream channels which were winding 
and irregular, but usually V-shaped in cross-section. A fresh 
flow of lava, after moving over such a surface, would cool the 
slowest of all in the heart of the former winding ravines, where 
