up is a trap sheet notched on its lower edge. At the left 
base of the mountain lies the lesser arch. 
" Figure 23 gives a section exhibited by one of the north- 
ward canons. It shows one of the faults of the upper part of 
the arch and illustrates the thinning of the sheets as they 
descend. ^ 
Page 118. 
"Mount Holmes, a few feet lower (than Mount Ellsworth) has 
the same flora, with the addition of a score of spruce trees, 
high up on the northern flank. Its summits are bare. 
i 
u In Figure 56 are the summit crags of Mount Holmes. They 
are dikes of trachyte denuded by a discriminating erosion of 
their encasements of sandstone, and carved in bold relief. In 
virtue of their superior hardness they survive the general 
degradation. 
Page 14-6 . 
"Turning now to Mount Holmes, we find that its two domes 
are not equally respected by the drainage lines. The crest of 
the Greater arch (see Figure 72) is the center of a radiating 
system, but the crest of the Messer arch is not:; and waterways 
arising on the Greater traverse the Lesser from side to side. 
More than this, a waterway after following the margin of the 
Lesser Arch turns toward it and penetrates the flank of the 
f 
arch for some distance. In a word , the drainage of the Greater 
arch is consequent on the structure, while the drainage of 
the Lesser Arch is inconsequent. 
