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 aeons buried 

 beneath the deposit of the Permian seas, and then, 

 during other aeons, 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 Canon. 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 canon 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 canon turned bottom side up, as it were. 



44 



