There are two types of rock art:
1.Petroglyphs are pecked, ground, or scratched into the rock surface.
2.Pictographs are paintings or drawings made on rock.
I have used 4 styles:
Archic 2000-4000 years old, some think 10,000 years old
Polychrome is oldest and abstact
Barrier is also very old and more anthropomorphic
Anasazi 300 AD to 1500 AD
Southern Utah, South eastern Colorado, North Eastern New Mexico
Fremont Style 500 AD to 1400 AD
mid to northern Utah
