Looking down canyon (to your left) is a graphic view of the geological
formations exposed in Walnut Canyon. On the next page of this guide
leaflet are sketches showing "How the Canyon was Formed."
No. 1. Millions of years ago this area was a vast flood plain near sea
level. Shifting sands were formed into dunes by wind causing cross
bedding or lamination. It is these sands that form the Toroweap
Formation which is the oldest exposed in the canyon and is the whorled
and cross-bedded sandstone which rises from the Canyon floor.
No. 2. Later this flood plain was submerged, and for millions of years
was at the floor of a large, shallow body of water called "The Permian
Sea." Calcium carbonate was precipitated to the floor of the sea. Small
sea animals were trapped or covered by this ooze or mire which later
compacted into stone and forms the Kaibab Limestone which forms the rim
of the canyon, and rests directly on the Toroweap. Many marine fossils
are found in this formation.
No. 3. A gradual uplifting of the earth's surface caused the sea to
retreat. Streams draining the land began cutting channels to the sea.
The gradual uplift coupled with the cutting action of the stream
facilitated canyon cutting. Erosion carried away later Cretaceous
deposits from the rim and side erosion began widening the channels.
Softer strata would erode more rapidly than the hard, forming the caves
in which man later built his homes.
No. 4. Volcanic activity and the forming of the San Francisco Peaks
during the next period increased erosion. This activity has continued
until fairly recent times. The latest eruption was that of Sunset
Crater, occurring around 1066 A.D. Walnut Canyon was dammed to form Lake
Mary in 1904. Otherwise there would be running water in the canyon most
of the year.
_There are practically no records of poisonous snakes at Walnut
Canyon. In summer the Coral King Snake with colorful black, white, and
orange-red bands may be seen. This snake is harmless and should not be
disturbed._