Northern In the northern portion of the McCullough Range elevation spans from at the eastern base of the range to at
Black Mountain. The peaks are volcanic in origin, rounded to flat-topped, and have a steep eastern escarpment and a gradual western slope. The area supports a unique combination of plants from the
Mojave and
Sonoran deserts and
Great Basin Desert ecosystems. The primary vegetation is a
creosote bush community with
barrel cactus (
Ferocactus cylindraceus),
Joshua trees (
Yucca brevifolia), various
chollas (
Cylindropuntia spp.) and
prickly pears (
Opuntia spp.). Unlike other mountain ranges in Clark County, the McCullough Range is volcanic in origin. Examples of lava flows, ash falls and glassy zones are clearly visible. The area supports native
black gramma grass (
Bouteloua eriopoda), which is not known to occur anywhere else in Nevada and stands of
teddy bear cholla (
Cylindropuntia bigelovii), which is the northernmost extent of the species. Remarkable
petroglyph panels and other important cultural resource features occur within the wilderness area. Another peak northeast of Black Mountain is home to most of the radio and television transmission towers for the Las Vegas Valley.
Southern The southern portion consists of a north–south mountain range that drops off gradually to numerous valleys, foothills and sloping
bajadas on the east and west flanks. Elevations range from in the northwest portion of the area to at McCullough Mountain in the center of the wilderness. Most of the area is composed of metamorphosed
Precambrian rock,
granite, and
schist, although
basalt and
andesite flows occur in the northern reaches of the southern portion.
Creosote bush (
Larrea tridentata) scrub occurs below ; Joshua trees,
Mojave yucca (
Yucca schidigera), and other cacti occur between ;
blackbrush occurs between ;
pinyon-juniper occurs above . Scattered
mesquite/catclaw communities also occur in washes throughout the area. Signs of prehistoric and
Pre-Columbian habitation have been found in the area, including
rock art, occupation and settlement sites, and pinyon pine nut caches. This was part of the historic homeland of the
Mojave people. The
desert tortoise,
Nelson bighorn sheep,
Gambel's quail and
chukar are present. ==References==