22 



GROVE KARL GILBERT— DAVIS 



[Memoirs National 

 [Vol. XXI, 



A cross section drawn near this point and showing the dislocation which defines the " western 

 edge of the great Carboniferous mesa" is reproduced in facsimile in Figure 3. 



3 %&i~3ttG^*o /N2§^ -y^4v\/ 



fig. s.- 

 October 6: 



■Section at the mouth of the Colorado Canyon; from Gilbert's notebook, October 4, 1871. 



... I propose to call our boat (no. 3) the Trilobite. We managed to get off from Camp Crossing at 

 about ten A. M. Mr. Marvine accompanies us so far as to get a glimpse of the mouth of the Canon & then 



returns. We camp outside of the Canon & H & I start to climb the wall. H sickens (morally) at 



the first third of the climb & returns. I do not reach the top until after sunset though I started at about 1 P. M. 

 It is the hardest climb I ever undertook. . . . 



October 7 : 



. . . Last night I spent alone on the mountain at the foot of Big [Grand] Cafion. Having no blankets I 

 built a little fire in a sheltered spot among the rocks and hugged it all night, getting little sleep. The first thing 

 that daylight shows me is that I am on only the first terrace & the second rises 5 m. to the east and trends a 

 little S of east. There can be no doubt that it consists of yellow and red sandstone . . . and the best guess I 

 can make at its feet is yellow 600, red 1200; total 1800. 



Many years afterwards Gilbert told a friend that he had expected, when looking up at the 

 escarpment from the river, to make both ascent and descent before dark; that he was much 

 alarmed at finding himself compelled to spend the night on the "terrace" because "bad Indians" 

 were about; and that when trying to sleep he was actually frightened by hearing "pat, pat, pat," 

 like footsteps stealthily approaching, but the pats proved to be only the beating of his own 

 heart, audible in the extreme stillness of the solitude. 



The notebooks give details of the stratigraphic succession in the escarpment of the plateau: 

 Here is the limit of disturbance . . . The gravel accumulations in the wash valley are immense & prove 

 that a high barrier has once contained the waters of the valley. . . . Reached Camp [on river bank] at about 

 1 P. M. with a big tired on. Whiskey, coffee & a rest brought me around however . . . Broke camp about 2 

 P. M. & worked up the river a few miles, passing springs. The granite that we had at the mouth & which I 

 neglected to collect disappears on todays march & the strata descend so as to bring No. 2 below water." . . . 



On October 11, an entry is made about great joints in — 



the "red-wall" limestone as I may as well designate the heavy mass that it troubled me so to climb. . . . We 

 find as we proceed two long stretches of rowing water where the granite walls hold the river narrow with very 

 little debris at the foot. A sharp rapid intervenes and at the head of the upper a roaring rapid that gave us one 



too many. The leading boat, — M at the helm; H at the pole — wrecked or rather swamped & 



upset scattering its freight along the bottom & top of the river. I started at once with . . . [four oarsmen] to 

 save the floating debris. Some of the men are demoralized a little by the rapid & tomorrow I have volunteered 

 to steer a boat up. The granite continues to grow higher and is beautifully sculptured by pot-holes & sand 

 action. Much of the surface is smooth and glazed. 



