the mcdowell mountains covered with saguaro cacti, palo verde bushes, cholla cacti, and dead brush on the horseshoe loop trail

granite rocks metamorphic trail hiking horseshoe loop mcdowell sonoran preserve scottsdale desert landscape geology cholla cactus dead brush nature outdoors arizona usa america mountains saguaro carnegiea gigantea parkinsonia teddybear jumping cylindropuntia tourism travel vacation scenic harsh environment ecosystem sight solitude covered cacti palo verde bushes