Montinu'iil Valley, one of the most bizarre of nature's 

 efforts on this continent, is blood-red in color and sculp- 

 tured into shapes of the utmost fantasy for miles 



Moreover, some obviously lay about and rotted before they were 

 engulfed in the muds and silts that preserved them, and these 

 must have been immersed gently during prolonged floods or 

 more likely by permanent subsidences of the land; otherwise 

 they would have been smashed apart 



Today all the strata laid down above these Chinle beds have 

 been eroded away, and the wind, rain, and other forces are now 

 at work on the beds themselves. The result is a group of low 

 hills with small, shallow valleys meandering between them, 

 sometimes forming miniature canyons and modest cliffs made of 

 the upper strata of these ancient lake and stream beds and con- 

 taining these trees in a petrified condition. As the softer material 

 is washed away, the logs slowly emerge and many pieces of 

 them roll down into the hollows, where they now form jumbles 

 that look like the back lots of a giant sawmill. On closer inspec- 

 tion, these logs provide a host of further surprises. 



They are. of course, composed of solid stone, for the most part 

 a form of quartz known as chalcedony, which looks like glass 

 but is really composed of an aggregation of minute crystals. This 

 material is formed by deposition in cavities in other materials; 

 and, if traces of other minerals are present in the solution, the 

 resulting crystals come in various colors to which distinctive 

 names have been given — carnelian, sard, chrysoprase, bloodstone. 

 and so forth. When alternating light and dark bands are laid 

 down, agate, onyx, and sardonyx result. Between these are often 

 related minerals of the opal group, which in a few rarer forms 

 are gems. Opals are among the few minerals that are not 

 crystalline, and they are really dried-up deposits of a substance 

 known as silica jelly. They contain froin 3 to 10 per cent of 

 water. These ancient trees, after being buried in the silt, were 

 subjected to a long process of nature whereby they were, as may 

 be said, taken apart molecule by molecule, the cellulose and 

 other materials of their wood being replaced by these chalced- 

 onies and opals. However, since each part of a tree, often down 

 to each of its rings, contains varying amounts of different trace 

 minerals like iron, sulphur, and so forth, the quartz became 

 stained in different colors. The result is that, though now of 

 solid stone, these trees display every detail of their structure 

 down to the microscopic, in varied and often contrasting colors. 

 The thick bark is usually a rich, smooth, reddish brown; the 

 interior of the trunk a pale mauvish gray; and sections of roots 

 often bright yellow. But the variation is endless, and all kinds 

 of beautiful and grotesque kaleidoscopes of color turn up, 

 especially in places where the trees were cracked, where 

 lightning struck, or where they were otherwise wounded in life. 



As you wander about among these stone trees, you will find 

 all manner of unexpected things, like whole stumps with the 

 butts of their roots sticking up to the sky just as if they had been 

 uprooted only the day before. All these trees are broken into 

 neat sections by clean, transverse fractures, though in man> 

 places all the sections of whole trees lie exposed on the surface 

 together and in proper order. It is said that this almost regular 

 cracking is due to the rhythmic vibrations of ancient earthquakes 

 But there are tides that follow each other daily round and round 

 the earth through the rocks, just as ocean tides run through the 

 waters of its surface, so that all rocks are actually stretched and 

 compressed a little twice a day. These tensions and pressures are 

 exerted virtually in all directions, unlike those of earthquakes 

 which travel in one direction, and would be much more likeU 



to cause the regular sectioning; for the logs lie pointmg in all 

 directions. 



The trees have been identified as conifers related to an ancient 

 group known as the Araucarians, now confined to the southern 

 hemisphere. In some of the associated shale beds, however, are 

 also found the perfectly fossilized leaves and other parts of 

 various cycads, horsetails, and ferns. The three tree species have 

 the tongue-twisting names of Woodsworthia and Schilderia, the 

 relationships of which are unknown, and Araucarioxyla. Of 

 animals of their period, besides a crocodile-like reptile called a 



