350 The American Geologist. December, 1894 
Pictured Rucks. 
I had passed and repassed the "grand portal'" of the pictured rocks 
three different times and had once made a sketch of it, but it seems I 
had never ascertained the extent of its interest. In passing it lately, all 
the circumstances being favorable, we determined to enter the arch 
with our boat, and though our mast was only about 10 to 18 feet high, 
still the feeling, as we approached, was that we must take it down to be 
able to pass under the apex of the arch: but drawing nearer the mast 
seemed to shrink and the arcli to tower upward until our sail shook un- 
der a vault of 120 feet high. So much is the eye deceived by a general 
proportionate grandeur. Entering, we found ample room for a vast ship 
of war, with sails all standing, to conceal herself, turn round and come 
out. without impediment. Although the water is deep for three-fourths 
of the way, yet, at the far end of the cave there is, first, a pile of huge 
fallen blocks of sandstone, and beyond these a sand beach 50 to 60 feet 
wide. Excited by a work so magnificent. 1 determined to make it my 
observatory until I had ascertained its form and dimensions as accu- 
rately as expedition would permit. For this purpose, and to enjoy a 
romantic luxury. 1 resolved on spending a night where I need not call 
on the mountains to hide me. 
As there was a spice of danger in spending the night in this palace of 
winds and waves, I landed the party to encamp on the sands near the 
Doric rock, ami was then transported and left in the cave, with my 
nephew and instruments, the voyagers returning with the boat to the 
encampment. Here we were more securely imprisoned than Napoleon 
on St. Helena, the only means of escape being to climb over hanging 
rocks 200 feet high, or swim half of a mile of the lake, with water so 
cold as to stiffen us in one-eighth of that distance, and our provisions, a 
few sticks of wood, which we brought in the boat, and a bucket of bean 
sou]). But we gave ourselves no anxiety, for we had too much work to 
perform. Immediately we measured our base line, for triangulation, 
500 feet long, all within the cave of the great arch! 
At this part of the pictured rocks there is a table of sandstone about 
200 feet high, presenting to the lake a perpendicular wall of waving 
and angular outline for several miles. At the grand portal the rock juts 
out into a short peninsula by two curves, which come up like the curves 
from the shoulders in each side of the neck. At the end it is abruptly 
truncated, as if the head had been cut off. Into this truncated end en- 
ters the grand portal arch, about 120 feet high, and, penetrating about 
300 feet, terminates in two smaller arches. Near the far end. a cross 
arch, opening on each side of the neck, traverses the main cavern. 
Thus the ground plan, like that of ancient cathedrals, is a cross. In the 
portal, however, the head of the cross is double. We ventured to give 
names to the various apartments. 1st. The grand dome, opening in the 
grand portal. 2d and 3d. The first and second dormitories. 4th. The 
left wing of the cross. 5th. The righl wing of the cross. 6th. The 
vestry, with columns, groined arches and Gothic windows* communicat- 
ing with the right wing. 7th. The Egyptian labyrinths, consisting of 
