U.S. DEPARTMENT OF THE INTERIOR

The Sloan Canyon NCA Visitor Contact Station is open daily from 8 a.m. to 4:30 p.m. October 1 through May 31. From June 1 to September 30, the Contact Station is open Friday through Sunday from 8 a.m. to 4:30 p.m.

From St. Rose Parkway:

1) Turn south on Executive Airport Drive.

2) Continue straight as Executive Airport Drive turns into Via Inspirada and curves sharply changing into   Bicentennial Pkwy.

3) Turn right onto Via Firenze.

4) Turn left onto Savella Ave.

5) Turn right back onto Via Firenze. Paved road ends at Democracy Dr.

6) Turn right onto Democracy Dr. Democracy at this point is an unpaved, graveled road. Follow a short distance until you get to Nawghaw Poa Road, the first paved road to your left.

7) Turn left onto Nawghaw Poa Road. Trailhead and visitor contact station is at the end of this road.

***PLEASE NOTE***

This area is under construction and these directions may change without notice.

The present day serenity of Sloan Canyon National Conservation Area contrasts to its violent volcanic past. Sloan Canyon contains one of the best records of volcanic activity in the Las Vegas area and contains at least eight volcanoes that erupted from time to time millions of years ago. Volcanoes that have not erupted for a while, but which may erupt again, are considered dormant. Volcanoes that have not erupted for thousands of years are called extinct. All the volcanoes at Sloan Canyon are extinct.

Petroglyph Canyon

Petroglyph Canyon is recognized for the abundance of petroglyphs in this area. Petroglyphs contain designs that have been scratched, etched, or pecked into a rock surface by early Native Americans. The Petroglyph Canyon area is also home to 13 million year-old volcanoes of the Sloan Volcanic Section. The Sloan Volcanic Section consists of four volcanoes called Mount Hanna, Mt. Ian, Mount Sutor, and the Center Mountain Dome, and covers an area of 30 square miles. Petrogylph Canyon cuts through the Mt. Sutor volcano, composed of many coalescing volcanic domes. These volcanic domes are composed of viscous (sticky) lava that squeezes out of a volcanic vent like toothpaste. The lava rarely flows but stands above the vent and forms a volcanic dome. Domes can be over a mile in diameter and may be several thousand feet high. Good examples of volcanic domes which are modern are found in the Mono Craters just north of Bishop, California, and in the summit crater of Mt. St. Helens in Washington State. These volcanic domes are similar to the Mt. Sutor volcanic dome complex.

Rocks in Sloan Canyon have a rich volcanic past, and are classified as igneous. Igneous rocks (derived from the Latin word igneus, meaning “of fire”) are one of the three rock types, the others being sedimentary and metamorphic rock. Igneous rocks are formed through the cooling and solidification of magma (molten rock) either below the surface as intrusive rocks, or on the surface as extrusive rocks.  Dacite is the most abundant type of rock in this area. Dacite is a fine-grained extrusive igneous rock. It is generally gray in color, but may range from nearly white to black. It may also vary from brown to reddish brown, depending on the amount of iron oxide in the rock. Dacite contains black mica (biotite) and white feldspar (plagioclase). When biotite oxidizes, it takes on a golden sheen under direct sunlight and is referred to as brassy biotite.

If you look carefully on your hike up the canyon,you may observe areas of vertical banding. The vertical banding reflects flow patterns in the rock, and in general suggests that magma in the domes was emplaced vertically.

As well as vertical flow banding, in places the rock is also cut by vertical fractures. These fractures are formed by cooling or later tectonic forces and commonly cut across flow banding. The vertical fractures are more common in the hard glassy rock that cooled rapidly. These fractures are seen in the petroglyph gallery area.

Another prominent geologic feature is called rock stripes. They are parallel lines of large stones, and intervening stripes of dominantly finer material oriented down steep slopes. They were formed during a wetter and colder period during the Pleistocene Epoch and are due to frost action. The rocks are covered with desert varnish, also called desert patina which is a dark brown color.

Hidden Valley

Hidden Valley is unique and differs from other areas in Sloan because of the unique geological features. It contains dikes, breccia, columnar and tectonic joints, and spheroidal weathering. These features are the result of the numerous volcanoes that occurred here long ago.

There are a number of dikes located throughout this area. Dikes are sheet-like bodies of magma that cut through layers of rock. Dikes may form as vents in volcanic cones and are often vertically oriented.

Breccia, which is the Italian word for broken rock, can be seen at various places along this trail. Breccia is a rock similar to a conglomerate that can form in many ways. Volcanic Breccia in this area is formed by the crumbling of volcanic domes. Domes are very steep- sided and unstable and they tend to slump and sometimes explosively disintegrate. These processes result in a variety of rock fragments cemented together into a fine-grained groundmass called breccia.

Both columnar and tectonic joints are also seen here along the trail to Petroglyph Canyon. Columnar joints are formed through the cooling of hot rock masses, particularly lava. Tectonic joints or cracks form in hard rock that is stretched so greatly to the point that its brittle strength is exceeded. After this happens, the rock breaks into several pieces either at right angles or at some angle to the direction of stretching.

Another prominent geological feature to look for is spheroidal weathering. The process of spheroidal weathering is slower than other common types of weathering. Spheroidal weathering is a type of chemical weathering that creates rounded boulders. The rocks form at great temperatures such as 760 degrees Celcius and usually three sets of joints develop. When the rocks cool down and water flows through the rocks, the acid in the water combine with the minerals, and attack the angles of the rocks. Spheroidal weathering causes planes on the rock where water flow can penetrate from three directions and leads to the formation of rounded corners.

These plants are seen in the Mojave Desert at Sloan Canyon National Conservation area near Henderson, Nevada. Specifically they are found in the north entrance to Petroglyph Canyon, Hidden Valley, and the Dutchman Pass area. Plants have definite preferences as to where they live. Some prefer open desert, rocky slopes, volcanic mountains, or washes. The wildflowers on the west of Sloan Canyon bloom late March through May. Some of these plants flower abundantly in the spring but when summer temperatures arrive, they may shed their leaves and become dormant. The short few weeks of colorful beauty is worth the wait.  

Beavertail Cactus (Opuntia basilaris) 

The flattened ‘paddles’ or stem give the appearance of a beaver’s tail. Flowers are bright magenta and occur from March to June.  In spring, up to six flowers emerge from the top edge of a joint. The large red to purple pear shaped fruits are known as tunas and are a valuable food source to local animals. Native peoples of the Mojave desert collected the fruit by knocking the fruit off of the joints, and brushing off the sharp (and difficult to see) glochids with a handful of grass. The fruit and pads, once the glochids are removed is edible. Medicinal uses of beavertail include: reducing pain and healing cuts by applying a dressing made from the fleshy pads, or applying the interior pulp directly to open wounds.

Bristle Gilia (Langloisia setosissima)

The plant is small with stiff bristles. The flowers are light violet and are useful in attracting pollinating insects. Leaves are wedge shaped and the entire plant measures only about three inches across. This plant is found in the Dutchman Pass area of Sloan Canyon along the McCullough Hills trail. 

Brittlebush (Encelia farinose)

This plant stays in bloom the longest of the wildflowers and is part of the sunflower family. It can bloom for up to to six months. This plant can reach three feet tall and has large silvery leaves. During the summer, the leaves dry and fall away leaving only stems. The stems were burned and used as incense by the early Spanish explorers because of its unique sweet smell.

Chia  (Salvia columbariae)

Chia is an annual plant that can grow to a height of one foot. The square stem has crinkled leaves and it has a strong minty odor. The seeds are high in protein and folklore has said that a person can survive for a long time on a solution of water and chia seeds. Antelope ground squirrels, birds, and mice use the seeds as food.

Creosote Bush (Larrea tridentate)

The Creosote Bush is often the dominant shrub of the gravel plains, sandy flats, and rocky slopes of the southwest desert.  It can be identified by its its small yellowish-green leaves and dime-sized five petal yellow flowers.  When pollinated, the flowers turn into small fuzzy white fruits. The pungent resins on the leaves along with the plant’s ability to drop its leaves in extreme heat make it a master at preventing water loss. The Creosote can continue to manufacture the sugars it needs for growth long after the dryness of the soil has forced other plants into dormancy.

The strong scent of a Creosote Bush hints at its chemical makeup and its medicinal value to the native peoples of the Southwest. Tribes used the bush as an antibiotic. A dry powder was made from leaves and used as an effective antibacterial agent for cuts, burns and abrasions. Decoctions and teas were used to treat ailments such as rheumatism, constipation, and cramps while inhaling the boiled vapors was thought to relieve respiratory ailments.

Desert Chicory (Rafinesquia neomexicana)

The chicory is a weak, fragile-stemmed annual that is common when a good spring flower season occurs. This white flower, which is in the Sunflower family, is similar to that of the common dandelion. It is often found growing under protective cover of shrubs where shading tends to reduce moisture loss. It blooms from April to June in washes and on slopes and is found along the Hidden Valley and Cowboy trail.

Desert Dandelion (Malacothrix glabrata)

Depending on rainfall, it may produce numerous blossoms or just a few. It grows on rolling hills and has carpeted many areas with colorful creations in heavy rainfall years.The bright yellow flowers are a favorite of the desert tortoise. They are found at the Dutchman Pass area of Sloan Canyon on the McCullough Hills Trail.

Desert Trumpet (Eriogonum inflatum) 

The Desert Trumpet is a perennial plant of the family Polygonaceae. The plant possesses very small yellow or pink flowers and an inflated stem just below branching segments.

The swollen stem of the Desert Trumpet is due to high concentrations of carbon dioxide in the solid stem and seems to be related to gas regulation. It is speculated that the inflation may be an adaptation to living in a harsh desert environment.

It is known that some Native American tribes that once inhabited the surrounding areas of the Las Vegas Valley (most commonly Paiute) would remove the stalk of Desert Trumpet at the base, and then cut the inflated bulb in half, producing a makeshift pipe. A mixture of Indian Tobacco and Mistletoe would then be smoked. 

Fiddleneck (Amsinckia tessellate)

The green flower stems have a dense covering of stiff prickly hairs. They bear many small yellow flowers which curl in a manner reminiscent of the head of a fiddle(violin). The foliage is poisonous to some forms of wildlife. The sharp hairs of the plant can also cause skin irritation in humans. They are found in the Dutchman Pass area of Sloan Canyon along the McCullough Hills trail.

Fremont Pincushion (Chaenactis Fremonii) 

The little annual is one of the most abundant flowers to be found in a good flower year. It is within the Sunflower family and is also called the morning bride flower. It prefers sandy soils in washes. It often grows around the bases of creosote bushes.

Globemallow (Sphaeralcea ambigua)

Globemallow is an upright shrustems arising from the base. The plant blooms profusely in the spring and occasionally at other times of year after wet weather. The bright orange flowers are 1 ½ inches in diameter, goblet shaped and grow in clusters along the upper stems of the plant. Desert Globemallow are browsed by bighorn sheep and the flowers often attract bees. The leaves are pale greenish, three-lobed, crinkled, and covered with dense, fine gray hairs. Globemallow is a common component of desert scrub communities on flats and bajadas.

There is a belief that the hairs of the plant are irritating to the eyes has given the name ‘sore-eye poppy’ and “mal de ojo.”

Mojave Yucca (Yucca schidigera)

This plant is a common yucca that normally has a trunk and can reach up to eight feet tall. It has yellowish green spines with white fibers attached. The Native Americans used the ivory flowers as food and the white fibers in weaving to make rope, baskets, and sandals. The Mojave yucca is seen at the north entrance to Petroglyph Canyon, Hidden Valley and the Dutchman Pass area.

Notch Leaf Phacelia (Phacelia crenulata)

The sap of this plant is toxic and may cause skin rash very similar to poison oak. It may obtain a height of one to two feet and is often called scorpion weed. The leaves are notched along the margins. It grows on rolling hillsides and slopes.

Rosy Two-Tone Beardtongue (Penstemon bicolor)

Penstemon are some of the most attractive flowers. The rosy two-tone beardtongue has bright pink flowers. Penstemon bicolor is a species of penstemon known by the common name rosy two-tone beardtongue.  It is native to the desert mountains and valleys of southern   Nevada, eastern California, and western Arizona, where it grows along roadsides, volcanic soils, and other local habitat. About 92 percent of the Nevada occurrences of these plants are on public lands managed by the Bureau of Land Management, with most of the remainder on privately managed lands.  It is under close watch by the federal agencies. It is vulnerable to activities which may affect their survival.

Sundrop (Camissonia brevipes)

This is one of the most noticeable of several different kinds of primroses in the region. It may grow to a height of two feet and is in the evening primrose family. It is an abundant plant and a very important food for wildlife, especially bighorn sheep.

Teddybear Cholla Cactus (Opuntia bigelovii) 

The plant has a soft appearance due to its solid mass of very formidable spines that completely cover the stems. From a distance, the stems appear soft and fuzzy, giving it the name "teddy bear".

The teddy-bear cholla is an erect plant, stanging one to five feet (0.30 to 1.5 m) tall with a distinct trunk. The branches are at the top of the trunk and are nearly horizontal.  Lower branches typically fall off, and the trunk darkens with age.

Like its cousin the jumping cholla, the stems of this cactus detach easily and the ground around a mature plant is often littered with scattered cholla balls and small plants starting where these balls have rooted. When a piece of this cholla sticks to an unsuspecting person, a good method to remove the cactus is with a hair comb. The spines are barbed, and hold on tightly. Desert pack rats such as the Desert Woodrat gather these balls around their burrows, creating a defense against predators.

The teddy-bear cholla is extremely flammable.

White Bursage (Ambrosia dumosa)

 Ambrosia dumosa, the burro-weed or white bursage, is a common constituent of the creosote-bush scrub community throughout the Mojave desert of California, Nevada, and Utah and the Sonoran Desert of Arizona and northwestern Mexico.

Ambrosia dumosa has been determined allelopathic interactions with creosote bush, Larrea tridentata, which produces a chemical that inhibits the growth of white bursage. Other studies have suggested that roots produce a chemical that causes them to grow away from roots, preventing competition for water resources. In addition to burro-weed, A. dumosa is also commonly called bursage, burro weed, and burro bush.

White Desert Primrose

This is one of the most fragrant of flowers. The white blossoms often turn pink before wilting and it is the evening-primrose family . They are found mainly in rocky soils along the north entrance to Petroglyph Canyon. 

White-Margined Beardtongue (Penstemon albomarginatus)

Penstemon are some of the most attractive flowers. It occurs on sand deposits and is an uncommon species of penstemon known by the common name white-margined beardtongue. It is native to the deserts of southern Nevada, western Arizona, as well as California. Flowers bloom from March to May and the flowering does not always seem to be dependent on amount of rainfall. Established plants may bloom even in very dry years by utilizing water and food resources in the large taproot.