MEASURING THE WALLS. 47 
The wind annoys us much to day. The water, rough by reason of the 
rapids, is made more so by head gales. Wherever a great face of rock has 
a southern exposure, the rarified air rises, and the wind rushes in below, 
either up or down the canon, or both, causing local currents. 
Just at sunset, we run a bad rapid, and camp at its foot. 
July 9. Our run to day is through a canon, with ragged, broken walls, 
many lateral gulches or canons entering on either side. The river is rough, 
and occasionally it becomes necessary to use lines in passing rocky places. 
During the afternoon, we come to a rather open canon valley, stretching up 
toward the west, its farther end lost in the mountains. From a point to 
which we climb, we obtain a good view of its course, until its angular walls 
are lost in the vista. 
July 10. Sumner, who is a fine mechanist, is learning to take observa 
tions for time with the sextant. To day, he remains in camp to practice. 
Howland and myself determine to climb out, and start up a lateral 
canon, taking a barometer with us, for the purpose of measuring the thick 
ness of the strata over which we pass. The readings of a barometer below 
are recorded every half hour, and our observations must be simultaneous. 
Where the beds, which we desire to measure, are very thick, we must climb 
with the utmost speed, to reach their summits in time. Again, where there 
are thinner beds, we wait for the moment to arrive ; and so, by hard and 
easy stages, we make our way to the top of the canon wall, and reach the 
plateau above about two o'clock. 
Howland, who has his gun with him, sees deer feeding a mile or two 
back, and goes off for a hunt. I go to a peak, which seems to be the highest 
one in this region, about half a mile distant, and climb, for the purpose of 
tracing the topography of the adjacent country. From this point, a fine 
view is obtained. A long plateau stretches across the river, in an easterly 
and westerly direction, the summit covered by pine forests, with intervening 
elevated valleys and gulches. The plateau itself is cut in two by the caiion. 
Other side canons head away back from the river, and run down into the 
Green. Besides these, deep and abrupt canons are seen to head back on 
the plateau, and run north toward the Uinta and White Rivers. Still other 
canons head in the valleys, and run toward the south. The elevation of the 
