TIME AND CHANGE 
serted camp, or one upon which the silence of death 
had fallen. Here, in Carboniferous times, grew the 
gigantic fern-like trees, the Sigillaria and Lepido- 
dendron, whose petrified trunks, for eons buried 
beneath the deposit of the Permian seas, and then, 
during other xons, slowly uncovered by the gentle 
action of the eroding rains, we saw scattered on the 
ground. 
You first see Nature beginning to form the cafion 
habit in Colorado and making preliminary studies 
for her masterpiece, the Grand Cafion. Huge 
square towers and truncated cones and needles and 
spires break the horizon-lines. Here all her water- 
courses, wet or dry, are deep grooves in the soil, with 
striking and pretty carvings and modelings adorn- 
ing their vertical sides. In the railway cuts you see 
the same effects — miniature domes and turrets and 
other cafion features carved out by the rains. The 
soil is massive and does not crumble like ours and 
seek the angle of repose; it gives way in masses like 
a brick wall. It is architectural soil, it seeks ap- 
proximately the right angle — the level plain or 
the vertical wall. It erodes easily under running 
water, but it does not slide; sand and clay are in 
such proportions as to make a brittle but not a 
friable soil. 
Before you are out of Colorado, you begin to see 
these novel architectural features on the horizon- 
line — the cafion turned bottom side up, as it were. 
4A 
