This seemed like an interesting perspective on many of the structures here. Regarding site 3, the guide talks about the source for mortar and the amount of erosion of the canyon wash.
Here is a picture of me taking this picture (a rare opportunity for you):
New Mexico is a state located in the southwestern region of the United States. Inhabited by Native American populations for many centuries, it has also been part of the Imperial Spanish viceroyalty of New Spain, part of Mexico, and a U.S. territory. Among U.S. states, New Mexico has the highest percentage of Hispanics at 45% (2008 estimate), being descendants of Spanish colonists and recent immigrants from Latin America. It also has the third-highest percentage of Native Americans after Alaska and Oklahoma, and the fifth-highest total number of Native Americans after California, Oklahoma, Arizona, and Texas. The tribes represented in the state consist of mostly Navajo and Pueblo peoples. As a result, the demographics and culture of the state are unique for their strong Spanish, Mexican, and Native American cultural influences. At a population density of 16 per square mile, New Mexico is the sixth most sparsely inhabited U.S. state.[http://en.wikipedia.org/wiki/New_mexico]