Lees Ferry is a site on the Colorado River in Coconino County, Arizona in the United States, about 7.5 miles southwest of Page and 9 miles south of the Utah–Arizona border. Due to its unique geography – the only place in hundreds of miles from which one can access the Colorado River from both sides – it served as an important river crossing and starting in the mid-19th century was the site of a ferry operated by John Doyle Lee, for whom it is named. Boat service at Lees Ferry continued for over 60 years before being superseded by a bridge in the early 20th century, which allowed for much more efficient automobile travel. Lees Ferry served as a military outpost for 19th-century settlements in Utah, a center of limited gold seeking and since the 1920s the principal point at which river flow is measured to determine water allocations in the 246,000-square-mile Colorado River basin. Lees Ferry demarcates the boundary between the Lower Basins of the Colorado River. Glen Canyon Dam impounds the Colorado a short distance upstream and regulates the river flow past Lees Ferry.
Lees Ferry has long been a focal point of American Southwest water disputes, has been called "both the physical and spiritual heart of water history in the arid West". Today Lees Ferry is a well-known fishing and boat launching point, including for whitewater rafting trips through the Grand Canyon. Lees Ferry is located in northern Arizona, at the point where the Paria River joins the Colorado from the north. Lying in an open valley directly downstream from Glen Canyon and shortly above Marble Canyon, it is the only place in more than 260 miles where the Colorado is not hemmed in by sheer canyon walls; this made it an important crossing point before the construction of Navajo and Glen Canyon Bridges in the 20th century. Here, the Colorado River is much smoother and calmer than the stretches that lie above and below. In the past, another crossing was the former Glen Canyon reach, but it is now flooded under Lake Powell, formed by Glen Canyon Dam 16 miles upstream. Lees Ferry is designated within the southwesternmost extreme of Glen Canyon National Recreation Area and is considered the northernmost end of Grand Canyon National Park.
It lies 689 miles upstream of the Colorado's mouth at the Gulf of California, at the approximate halfway mark of the river's length. The surrounding valley formed because of a swell in the underlying rock of the Colorado Plateau that caused the regional elevation to intersect the Chinle and Moenkopi Formations, deposited in the Triassic about 208–245 million years ago; this area contains sandstone, siltstone and limestone formed by the sediments on ancient seabeds and alluvial deposits made by the Colorado and Paria Rivers. Because these are more eroded than the rock layers that lie above and below them, the Colorado Plateau slopes down to river level at Lees Ferry through a series of flat benchlands. In pre-Columbian times, the Lees Ferry area was inhabited first by Paleo-Indians, who populated the region beginning about 11,500 years ago, followed by the Archaic culture, which appeared on the Colorado Plateau about 8,000 years ago; the Anasazi and Navajo peoples, who left more evidence of habitation in the valley, arrived only in the last 1,000 years or so.
Evidence, including the discovery of two ruins nearby on the Paria River, suggests that the Anasazi utilized the area sometime in the 12th century A. D. Nonetheless, indigenous peoples did not make extensive use of the Lees Ferry area and other canyon stretches of the Colorado River, preferring the open plains above for hunting. However, Lees Ferry did become a disputed territory between the Navajos and Paiutes, who recognized it as a valuable livestock watering point; the first Europeans who happened upon Lees Ferry were members of the 18th-century Dominguez-Escalante Expedition, an attempt to find an overland route through the Southwest between Spanish settlements in present-day New Mexico and California, in the process, to convert as many Southwestern Native Americans as possible to Christianity. In late 1776, the party ran out of supplies in what is now southern Utah and having decided to turn back towards Santa Fe, had to find a way to cross the Colorado River, their Native American guides told them of two regional fords of the river, one at the site of Lees Ferry and the other at Glen Canyon.
When the explorers arrived at Lees Ferry in October, they found the river too wide and deep and had no choice but to head for the second ford more than 40 miles upstream. Two weeks they crossed the river, made it back to Santa Fe on January 2, 1777; this point, now submerged under Lake Powell, is named Crossing of the Fathers after Francisco Atanasio Domínguez and Silvestre Vélez de Escalante, the two Franciscan priests who headed the expedition. During the 19th century, Lees Ferry served as a gateway for the expansion of white settlement from Utah south into Arizona. Most of the settlers were Mormons, long established in the Utah Valley near present-day Salt Lake City, were looking for additional land. Although the river at Lee's Ferry is too deep to ford for most of the year, its calm current presented an attractive site for crossing by boat. Jacob Hamblin crossed the river here in 1864, during the next few years the Mormon presence swelled to the scale of a small military outpost in order to defend against Navajo raids.
However, these works fell into disrepair a
The Tanner Trail is a hiking trail located on the South Rim of the Grand Canyon National Park, located in the U. S. state of Arizona. The trailhead is located at Lipan Point, a prominent lookout located to the east of the Grand Canyon Village and it ends at the Colorado River at Tanner Rapids; the Tanner Trail started out as an ancient Hopi route to the Colorado River. Most believe today that Tanner Canyon is where García López de Cárdenas became the first European to encounter the Grand Canyon; the trail is named after Seth Tanner, a 19th-century prospector who improved the trail so he would have better access to his copper mine. It is believed that Tanner Canyon was once used as an old horse thief trail where buried gold known as Long Tom's treasure is located; the horse thieves would use the canyon to bring the horses from Arizona into Utah. While in the canyon, the horse thieves would change the brands of the horses they would cross the Colorado River and drive the horses out of the canyon through the Nankoweap Trail up onto the North Rim.
The canyon was once named Horsethief Canyon in honor of this storied past. Entrance to the South Rim of the Grand Canyon can be accessed by two points: the south entrance via State Route 64 north from Williams, the east entrance via State Route 64 west from U. S. Route 89; the trailhead for the Tanner Trail is located near the parking area at Lipan Point, which can be accessed by the Desert View Drive. Hikers are advised to park at Lipan Point, as the trailhead is located just before the parking lot at Lipan Point; the Tanner trailhead begins at the information sign just before Lipan Point. The trail starts out by crossing the rim plateau to the canyon edge, it enters the Tanner Canyon and starts a series of switchbacks, which become steep and rocky. The descent is considered to be one of the steepest rim descents in the Grand Canyon; the trail goes through the Kaibab Formation and becomes steeper in the Coconino sandstone and the Hermit shale. It reaches the Supai group, where the ridge between Tanner Canyon and Seventyfive Mile Canyon is located.
The trail enters into the Tanner Canyon creek for a short time it leaves the creek. It makes a long yet moderate crossing of the Supai group. There are many suitable campsites along this stretch, while it passes Escalante and Cardenas Buttes; the trail descends into a boulder-strewn plateau. It turns to the north to the end of the plateau. At this point the trail makes its second major descent, dropping off the plateau into the lower Tanner Canyon. There are some switchbacks yet the trail descends straight down around 800 ft to a red saddle below where there are a few campsites. From the saddle, the trail levels out; the trail follows the west side of Tanner Canyon descending to the streambed below. When the streambed is reached, the trail crosses over to the east side and up onto the river plateau, it drops into the campground. Campsites can be found to the east and the west The trail is categorized as a primitive trail and receives little maintenance by trail crews and few patrols by park rangers.
This trail is only recommended for seasoned hikers, as it is steep, has little shade, the only water source is the Colorado River. The trail is well worn, easy to follow, although it is one of the longer trails in the Canyon. Extreme care and preparation should always be taken in attempting a trail in the Grand Canyon; the only reliable source of water along the Tanner Trail is the Colorado River. Seasonal water may be found in the Tanner Canyon. Hikers can check with the Backcountry Information Center for updates on all seasonal water sources, which are checked by other hikers and Park rangers. All water in the Grand Canyon must be treated before consumption; the National Park Service recommends boiling, iodine tablets, or filters in order to purify the water. If water is taken from the Colorado River, the Park recommends letting the water sit so the sediment will settle. Camping in the Tanner Trail area is at-large. There are multiple "campsites" along the trail, but the main camp area is located at Tanner Rapids, a spot, popular to rafters.
The camp area is located at the end of the Trail, situated between the dunes to west and the river to the east. The camp area has a pit toilet located in the middle of the campsites; the sand dunes to west are off-limits to camping and foot-travel, as the Park is attempting to revegetate and stabilize the area. Hazards hikers can encounter along the Tanner Trail include dehydration, heat stroke, sudden rainstorms, flash flooding, loose footing, encounters with wildlife, extreme heat, getting lost. At the Colorado River, additional hazards include hypothermia and drowning. Extreme care and preparation should always be used when entering the Grand Canyon. Hikers need to remember that the Grand Canyon is located in the desert, as such there are many dangerous desert species to watch out for; these include all types of scorpions, spiders, mice, big horn sheep, mountain lions. The most dangerous and venomous of these animals are the black widow spider, the Arizona bark scorpion, the rattlesnake. List of trails in Grand Canyon National Park Desert View Watchtower Tanner Graben at Tanner Rapid Grand Canyon National Park, Official site Grand Canyon Explorer Grand Canyon Planner The American Southwest Tanner Photos Grand Canyon Pictures and Reviews
International scale of river difficulty
The international scale of river difficulty is an American system used to rate the difficulty of navigating a stretch of river, or a single rapid. The scale was created by the American Whitewater Association to evaluate rivers throughout the world, hence international in the title, it should not be confused with the internationally used whitewater scale, published and adapted by a committee of the International Canoe Federation ICF. The grade reflects the technical difficulty and skill level required associated with the section of river; the scale is of use to various water sports and activities, such as rafting, whitewater canoeing, stand up paddle surfing, whitewater kayaking. There are six categories, each referred to; the scale is not linear, nor is it fixed. For instance, there can be difficult grade twos, easy grade threes, so on; the grade of a river may change with the level of flow. A river or rapid will be given a numerical grade, a plus or minus to indicate if it is in the higher or lower end of the difficulty level.
While a river section may be given an overall grading, it may contain sections above that grade noted as features, or conversely, it may contain sections of lower graded water as well. Details of portages may be given. A summary of river classifications as presented by the American Whitewater Association: Classifications can vary enormously, depending on the skill level and experience of the paddlers who rated the river. For example, at the 1999 International Conference on Outdoor Recreation and Education, an author of a paddling guide pointed out that there is too much variation in what is covered by the Class I designation, proposed making further distinctions within the Class I flat water designations and Class I+ moving water designations, with the goal of providing better information for canoeists, instructors leading trips, families with young children; the grade of a river or rapid is to change along with the level of the water. High water makes rapids more difficult and dangerous, although some rapids may be easier at high flows because features are covered or washed out.
At spate/flood stage rapids which are easy can contain lethal and unpredictable hazards. Conversely, some rapids may be easier with lower water levels when dangerous hydraulics become easier to manage; some rivers with high volumes of fast moving water may require little maneuvering, but will pose serious risk of injury or death in the event of a capsize. Degree of difficulty
California is a state in the Pacific Region of the United States. With 39.6 million residents, California is the most populous U. S. the third-largest by area. The state capital is Sacramento; the Greater Los Angeles Area and the San Francisco Bay Area are the nation's second and fifth most populous urban regions, with 18.7 million and 9.7 million residents respectively. Los Angeles is California's most populous city, the country's second most populous, after New York City. California has the nation's most populous county, Los Angeles County, its largest county by area, San Bernardino County; the City and County of San Francisco is both the country's second-most densely populated major city after New York City and the fifth-most densely populated county, behind only four of the five New York City boroughs. California's $3.0 trillion economy is larger than that of any other state, larger than those of Texas and Florida combined, the largest sub-national economy in the world. If it were a country, California would be the 5th largest economy in the world, the 36th most populous as of 2017.
The Greater Los Angeles Area and the San Francisco Bay Area are the nation's second- and third-largest urban economies, after the New York metropolitan area. The San Francisco Bay Area PSA had the nation's highest GDP per capita in 2017 among large PSAs, is home to three of the world's ten largest companies by market capitalization and four of the world's ten richest people. California is considered a global trendsetter in popular culture, innovation and politics, it is considered the origin of the American film industry, the hippie counterculture, fast food, the Internet, the personal computer, among others. The San Francisco Bay Area and the Greater Los Angeles Area are seen as global centers of the technology and entertainment industries, respectively. California has a diverse economy: 58% of the state's economy is centered on finance, real estate services and professional, scientific and technical business services. Although it accounts for only 1.5% of the state's economy, California's agriculture industry has the highest output of any U.
S. state. California is bordered by Oregon to the north and Arizona to the east, the Mexican state of Baja California to the south; the state's diverse geography ranges from the Pacific Coast in the west to the Sierra Nevada mountain range in the east, from the redwood–Douglas fir forests in the northwest to the Mojave Desert in the southeast. The Central Valley, a major agricultural area, dominates the state's center. Although California is well-known for its warm Mediterranean climate, the large size of the state results in climates that vary from moist temperate rainforest in the north to arid desert in the interior, as well as snowy alpine in the mountains. Over time and wildfires have become more pervasive features. What is now California was first settled by various Native Californian tribes before being explored by a number of European expeditions during the 16th and 17th centuries; the Spanish Empire claimed it as part of Alta California in their New Spain colony. The area became a part of Mexico in 1821 following its successful war for independence but was ceded to the United States in 1848 after the Mexican–American War.
The western portion of Alta California was organized and admitted as the 31st state on September 9, 1850. The California Gold Rush starting in 1848 led to dramatic social and demographic changes, with large-scale emigration from the east and abroad with an accompanying economic boom; the word California referred to the Baja California Peninsula of Mexico. The name derived from the mythical island California in the fictional story of Queen Calafia, as recorded in a 1510 work The Adventures of Esplandián by Garci Rodríguez de Montalvo; this work was the fifth in a popular Spanish chivalric romance series that began with Amadis de Gaula. Queen Calafia's kingdom was said to be a remote land rich in gold and pearls, inhabited by beautiful black women who wore gold armor and lived like Amazons, as well as griffins and other strange beasts. In the fictional paradise, the ruler Queen Calafia fought alongside Muslims and her name may have been chosen to echo the title of a Muslim leader, the Caliph. It's possible.
Know ye that at the right hand of the Indies there is an island called California close to that part of the Terrestrial Paradise, inhabited by black women without a single man among them, they lived in the manner of Amazons. They were robust of body with great virtue; the island itself is one of the wildest in the world on account of the craggy rocks. Shortened forms of the state's name include CA, Cal. Calif. and US-CA. Settled by successive waves of arrivals during the last 10,000 years, California was one of the most culturally and linguistically diverse areas in pre-Columbian North America. Various estimates of the native population range from 100,000 to 300,000; the Indigenous peoples of California included more than 70 distinct groups of Native Americans, ranging from large, settled populations living on the coast to groups in the interior. California groups were diverse in their political organization with bands, villages, on the resource-rich coasts, large chiefdoms, such as the Chumash and Salinan.
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The Grand Canyon is a steep-sided canyon carved by the Colorado River in Arizona, United States. The Grand Canyon is 277 miles long, up to 18 miles wide and attains a depth of over a mile; the canyon and adjacent rim are contained within Grand Canyon National Park, the Kaibab National Forest, Grand Canyon-Parashant National Monument, the Hualapai Indian Reservation, the Havasupai Indian Reservation and the Navajo Nation. President Theodore Roosevelt was a major proponent of preservation of the Grand Canyon area, visited it on numerous occasions to hunt and enjoy the scenery. Nearly two billion years of Earth's geological history have been exposed as the Colorado River and its tributaries cut their channels through layer after layer of rock while the Colorado Plateau was uplifted. While some aspects about the history of incision of the canyon are debated by geologists, several recent studies support the hypothesis that the Colorado River established its course through the area about 5 to 6 million years ago.
Since that time, the Colorado River has driven the down-cutting of the tributaries and retreat of the cliffs deepening and widening the canyon. For thousands of years, the area has been continuously inhabited by Native Americans, who built settlements within the canyon and its many caves; the Pueblo people considered the Grand Canyon a holy site, made pilgrimages to it. The first European known to have viewed the Grand Canyon was García López de Cárdenas from Spain, who arrived in 1540; the Grand Canyon is a river valley in the Colorado Plateau that exposes uplifted Proterozoic and Paleozoic strata, is one of the six distinct physiographic sections of the Colorado Plateau province. It is not the deepest canyon in the world. However, the Grand Canyon is known for its visually overwhelming size and its intricate and colorful landscape. Geologically, it is significant because of the thick sequence of ancient rocks that are well preserved and exposed in the walls of the canyon; these rock layers record much of the early geologic history of the North American continent.
Uplift associated with mountain formation moved these sediments thousands of feet upward and created the Colorado Plateau. The higher elevation has resulted in greater precipitation in the Colorado River drainage area, but not enough to change the Grand Canyon area from being semi-arid; the uplift of the Colorado Plateau is uneven, the Kaibab Plateau that Grand Canyon bisects is over one thousand feet higher at the North Rim than at the South Rim. All runoff from the North Rim flows toward the Grand Canyon, while much of the runoff on the plateau behind the South Rim flows away from the canyon; the result is deeper and longer tributary washes and canyons on the north side and shorter and steeper side canyons on the south side. Temperatures on the North Rim are lower than those on the South Rim because of the greater elevation. Heavy rains are common on both rims during the summer months. Access to the North Rim via the primary route leading to the canyon is limited during the winter season due to road closures.
The Grand Canyon is part of the Colorado River basin which has developed over the past 70 million years, in part based on apatite /He thermochronometry showing that Grand Canyon reached a depth near to the modern depth by 20 Ma. A recent study examining caves near Grand Canyon places their origins beginning about 17 million years ago. Previous estimates had placed the age of the canyon at 5–6 million years; the study, published in the journal Science in 2008, used uranium-lead dating to analyze calcite deposits found on the walls of nine caves throughout the canyon. There is a substantial amount of controversy because this research suggests such a substantial departure from prior supported scientific consensus. In December 2012, a study published in the journal Science claimed new tests had suggested the Grand Canyon could be as old as 70 million years. However, this study has been criticized by those who support the "young canyon" age of around six million years as " attempt to push the interpretation of their new data to their limits without consideration of the whole range of other geologic data sets."The canyon is the result of erosion which exposes one of the most complete geologic columns on the planet.
The major geologic exposures in the Grand Canyon range in age from the 2-billion-year-old Vishnu Schist at the bottom of the Inner Gorge to the 230-million-year-old Kaibab Limestone on the Rim. There is a gap of about a billion years between the 500-million-year-old stratum and the level below it, which dates to about 1.5 billion years ago. This large unconformity indicates a long period. Many of the formations were deposited in warm shallow seas, near-shore environments, swamps as the seashore advanced and retreated over the edge of a proto-North America. Major exceptions include the Permian Coconino Sandstone, which contains abundant geological evidence of aeolian sand dune deposition. Several parts of the Supai Group were deposited in non–marine environments; the great depth of the Grand Canyon and the height of its strata can be attributed to 5–10 thousand feet of uplift of the Colorado Plateau, starting about 65 million years ago. This uplift has steepened the stream gradient of the Colorado River
Phantom Ranch is a lodge inside Grand Canyon National Park in Arizona. It is on the north side of the Colorado River near its confluence with Bright Angel Creek and Phantom Creek. Built in 1922, Phantom Ranch is a member of Historic Hotels of America, the official program of the National Trust for Historic Preservation; the site where the ranch is now was used by Native Americans. The earliest recorded visit by non-Native Americans took place in 1869, when John Wesley Powell and his company camped at its beach. Prospectors began using mules to haul their ore. At the turn of the 20th century, the founders of the Grand Canyon Transportation Company began a project to exploit its tourism potential, hiring a crew to improve the trail from Phantom Ranch to the Canyon's North Rim. President Theodore Roosevelt traveled down the canyon to the camp during a hunting expedition in 1913. Roosevelt's enthusiasm for the Grand Canyon helped lead to its incorporation into the National Park System in 1919; the Fred Harvey Company was granted the concession for the camp in 1922.
Colter suggested. Construction presented a major challenge: all the building materials except rock had to be hauled down by mules. Meeting the challenges at this and other national parks led to the architectural style known as National Park Service Rustic, which features native stone, rough-hewn wood, large-scale design elements, intensive use of hand labor. During the Great Depression in the 1930s, the Civilian Conservation Corps made a number of improvements to the ranch and its access trails; the 1920s and 1930s saw its popularity grow, it was visited by many wealthy and notable guests. The Fred Harvey company made it a point to hire young, well-educated, adventurous women to staff the resort; as the Grand Canyon's popularity grew, so did Phantom Ranch's. The National Park Service instituted a permit system for overnight stays at the ranch; the ranch remains a popular destination. Beginning in 2019, reservations will be issued monthly via a lottery system; the site includes cabins, two dormitories each for men and women, a restaurant, a mule corral, emergency medical facilities, a ranger station, the Bright Angel Campground, a beach visited by Colorado River rafters, a heliport.
Cottonwood trees shade the buildings. The Bright Angel Campground 1/2 mile from Phantom Ranch, has 32 campsites, including two large group sites; the only modes of access to the ranch are the Colorado River. The North Kaibab Trail leads 14 miles to the North Rim; the 9.3-mile trail to the South Rim follows the River Trail for two miles and climbs the Bright Angel Trail to Grand Canyon Village. The two trail bridges near the ranch are the only Colorado River crossings within a several-hundred-mile span. Phantom Ranch has no official mail service, but concessionaires have traditionally transported letters and postcards by mule. Packages are excluded from this service. Phantom Ranch's elevation is 2,460 feet; the average daily high and low temperatures are 106 °F /78 °F during July and 56 °F /36 °F in January. This represents a wide differential from temperatures at the top of the Grand Canyon; the South Rim averages 58 inches of snow, Phantom Ranch less than 1 inch. The riparian zone at the ranch is subject to invasion by non-native species such as tamarix, volunteers are at times invited to help maintain the original biome by removing them.
The ranch is located at 36°06′18″N 112°05′40″W. Thybony, Scott. Phantom Ranch. Grand Canyon, AZ: Grand Canyon Assn. ISBN 978-0-938216-76-6. -- This 32-page book reveals the people who made that history. Touches on the flora and fauna of Grand Canyon; the author is former river guide. Grand Canyon official website History of Phantom Ranch National Park Service Rustic Architecture
The Hermit Trail is a hiking trail in Grand Canyon National Park, located in the U. S. state of Arizona. This trail provides access to a historic area of Grand Canyon and offers a more challenging route to the Colorado River for more experienced canyon hikers; the trailhead is located 0.25 miles southwest of Hermit's Rest on the South Rim of the Grand Canyon. The trailhead is accessible by shuttle bus from Grand Canyon Village, Arizona on the Hermit Road; the road is closed to private vehicles between April and October annually, is open to all traffic other months. Two exceptions are for vehicles with government issued handicap placards and backpackers with valid permits for overnight camping in the Hermit use area; those users can obtain the gate code by visiting the Backcountry Information Center in the park. Grand Canyon National Park categorizes the Hermit Trail as a threshold trail and does not maintain it; the trail is rutted in many places, the once exquisite construction of placed stones on the upper half of the trail is now crumbling and rough.
Numerous rockslides require rock scrambling and route finding to pass. The most recent major rockslide occurred in the evening of 1 March 1983, when a large section of rock in the Supai Group broke away from a cliff face and scattered down Hermit Canyon, cutting the Hermit Trail in two places. A rockslide that took place in the early 1930s cuts through the trail in a third place; these breaks in the trail are well marked with cairns. All water sources along this trail must be filtered, or boiled before drinking. Water is available year-round at the Colorado River; the trail between the Hermit Creek camping area and the Colorado River parallels Hermit Creek and provides additional water accessibility. Water flows periodically from Santa Maria Spring, located 2 trail miles in from the trailhead, but should not be counted on. Hermit Creek above the Hermit Creek campsite is dry except in time of flash flood; the park's Backcountry Information Center has current water conditions for all water sources along the Hermit Trail.
There are two designated campsites in the Hermit Use Area. The three letter code indicates the park's use area designation: BM7 - Hermit Creek / Up to 23 persons for 1 group and 3 parties. BM8 - Hermit Rapids / Up to 17 persons for 1 group and 1 party. Use permits are available on a first-come, first-served basis from the park's Backcountry Information Center. Requests are taken beginning on the 1st day of the month, up to four months before the requested first night of camping. Hazards hikers can encounter along the Hermit Trail include dehydration, sudden rainstorms, flash flooding, loose footing, encounters with wildlife, extreme heat. At the Colorado River, additional hazards include hypothermia and drowning; this trail was built in the last decade of the 19th century by horsetheives, but was improved by different prospectors of that era. The Atchison and Santa Fe Railway improved the trail further around 1910 to compete with the Camerons' Bright Angel Trail which charged a toll at the time.
The railroad operated Hermit Camp about 7 trail miles below the rim until the 1930s when the National Park Service took over control of the Bright Angel Trail and rescinded its tolls. Major rocks along this trail include limestone, chalk and other sedimentary rocks, as well as obsidian and igneous rocks. Rocks by the Colorado River are heavily weathered; some of the limestone is fossiliferous representing bivalves. List of trails in Grand Canyon National Park Grand Canyon National Park, Official site Grand Canyon Explorer