Day 47 April 20

Early video game?

This one was probably done by a Spanish shepherd that had sheep in the late 1600s

We visited Petroglyph National Monument today. A Petroglyph is a picture that is scratched or carved into a rock. (In contrast to a pictograph, which is painted) In this case, the majority of the petroglyphs we were looking at were made between the 1300's and the 1700's and were created by an Ancestral Pueblo culture.


 The rocks used for the petroglyphs originated from a layer of basalt caprock that formed 150,000 years ago, when a fissure in the earth's crust allowed lava to flow out. As the lava cooled, the fissure closed and five vents were created, which caused cinder cones to form. Over time, the underlying sediment eroded, and the cap rock crumbled, leaving the rocky landscape that we see today. The basalt rocks contain high amounts of iron, manganese, and calcium, which makes them naturally light gray. After exposure to the elements, however, these minerals oxidize causing a dark patina to form. This "rust" on the outside of the rocks is called "desert varnish." American Indians created the petroglyphs by using another rock to peck or chisel off the desert varnish, revealing the true color of the basalt. Some of the petroglyphs seem easy to interpret, but others are not as readily understood.

bird

Space craft visiting the Indians?



Four of the Cinder Cones off in the distance.