Channel Islands National Park
Channel Islands National Park is a United States national park that consists of five of the eight Channel Islands off the coast of the U. S. state of California, in the Pacific Ocean. Although the islands are close to the shore of densely populated Southern California, the park covers 249,561 acres of which 79,019 acres are owned by the federal government. The Nature Conservancy owns and manages 76% of Santa Cruz Island, Channel Islands National Park is home to a wide variety of significant natural and cultural resources. It was designated a U. S. National Monument on April 26,1938, and it was promoted to a National Park on March 5,1980. Channel Islands National Marine Sanctuary encompasses the waters six nautical miles around Channel Islands National Park, the Channel Islands were originally discovered in 1542 by the explorer Juan Rodríguez Cabrillo. In 1938 the Santa Barbara and Anacapa islands were designated a national monument, San Miguel, Santa Rosa and Santa Cruz islands were combined with the monument in 1980 to form modern-day Channel Islands National Park.
On January 28,1969 an oil rig belonging to Union Oil experienced a blow-out 6 miles off the coast of California, the resulting spill was, at the time, the largest oil spill to occur in United States territorial waters. Following the spill, tides carried the oil onto the beaches of the Anacapa, San Miguel, Santa Rosa and this spill had a large impact on native wildlife of the Channel Islands. Much of the seabird population was affected, with over an estimated 3,600 avians killed. Meanwhile, seals and other sea life died and washed ashore on both the islands and the mainland and this spill is the third largest oil spill in the United States, only surpassed by the Deepwater Horizon and the Exxon Valdez oil spills. It resulted in a 34,000 acres expansion of the Department of the Interior buffer zone in the channel, the islands within the park extend along the Southern California coast from Point Conception near Santa Barbara to San Pedro, a neighborhood of Los Angeles. Park headquarters and the Robert J.
Lagomarsino Visitor Center are located in the city of Ventura, only three mammals are endemic to the islands, one of which is the deer mouse which is known to carry the sin nombre hantavirus. The spotted skunk and Channel Islands fox are endemic, the island fence lizard is endemic to the Channel Islands. One hundred and forty-five of these species are unique to the islands, Marine life ranges from microscopic plankton to the endangered blue whale, the largest animal on earth. Archeological and cultural resources span a period of more than 10,000 years, the average annual visitation to the parks mainland visitor center was around 300,000 in the period from 2007 to 2016, with 364,807 visiting in 2016. The visitor center is located in the Ventura Harbor Village, the visitor center contains several exhibits that provide information regarding all five islands, native vegetation, marine life and cultural history. Also, visitors can enjoy a film, free of charge. The visitor center is open day, except Thanksgiving and Christmas, from 8, 30AM–5
Trione-Annadel State Park
Trione-Annadel State Park is a state park of California in the United States. It is situated at the edge of Sonoma Valley and is adjacent to Spring Lake Regional Park in Santa Rosa. It offers many activities within its 5, 092-acre property. These lands were occupied by the Wappo and Pomo people in times, who would have primarily inhabited the riparian zones. Annadel includes what some consider the best example of undisturbed northern oak woodlands in existence. Visitors can enjoy the parks wildlife and scenery during any time of the year but are perhaps most rewarded from April through June when most wildflowers are in bloom. Plant communities include California oak woodland, riparian woodland, Douglas fir forest, grassland, the dominant plant community is the oak woodland, which has a canopy of coast live oak, Garry oak, black oak, Pacific madrone, bigleaf maple, and California laurel. Canyon live oak occurs in swales and creeks, in the oak woodlands, the dominant understory plants are native bunchgrasses, wild blackberry, coyote brush, and western poison-oak.
The latter covers nearly one quarter of the understory in the park, Douglas fir occurs in some of the steeper, cooler riparian zones and on north-facing slopes. Common animals in Annadel include black-tailed deer, western gray squirrel, skunk and mountain lion are occasionally observed. There are many species, including the California scrub jay, Stellers jay, acorn woodpecker, black phoebe. In moist areas, amphibians such as the rough-skinned newt can be found, the southern reaches of Annadel are drained by Yulupa Creek and other tributaries of Sonoma Creek, while the northern flanks are part of the Santa Rosa Creek watershed. Eastern slopes are drained by Yulupa and Sonoma Creeks, while the slopes are part of the Spring Creek watershed. Many of Annadels streams are dry in the summer, because rainfall is highly seasonal, Ledson Marsh, which drains into Yulupa Creek, retains some smaller pools of water throughout most of the year. The highest elevation in the park is the top of Bennett Mountain,1,887 feet.
The entirety of Annadel was below the floor as recently as twelve million years ago, around which time massive uplift. Elevations in Annadel range from about 360 to 1,880 feet above sea level, slopes within Annadel commonly range from 15 to 30 percent, but it is not uncommon to encounter slopes up to 70 percent on steep slopes above drainages which are covered in douglas fir forest. Typical soil depths are 35 to 50 centimetres, much of the soil type in the Yulupa Creek riparian zone consists of Laniger loam, with rhyolite outcrops, another relic of the igneous history
Angel Island (California)
Angel Island is an island in San Francisco Bay offering expansive 360° views of the San Francisco skyline, the Marin County Headlands and Mount Tamalpais. The entire island is included within Angel Island State Park and is administered by California State Parks, Angel Island is the second largest island in area of the San Francisco Bay. The island is so large that on a day and Napa can be seen from the north side of the island. The highest point on the island, almost exactly at its center, is Mount Caroline Livermore at a height of 788 feet, the island is separated from the mainland of Marin County by Raccoon Strait, the depth of the water approximately 90 feet. The United States Census Bureau reported an area of 3.107 km². Until about ten years ago, Angel Island was connected to the mainland. From about two years ago the island was a fishing and hunting site for Coast Miwok Native Americans. Similar evidence of Native American settlement is found on the mainland of the Tiburon Peninsula upon Ring Mountain.
In 1775, the Spanish naval vessel San Carlos made the first European entry to the San Francisco Bay under the command of Juan de Ayala, Ayala anchored off Angel Island, and gave it its modern name, the bay where he anchored is now known as Ayala Cove. In his book Two Years Before the Mast, published in 1840, Richard Henry Dana, like much of the California coast, Angel Island was subsequently used for cattle ranching. In 1863, during the American Civil War, the U. S. Army was concerned about Confederate naval raiders attacking San Francisco and it decided to construct artillery batteries on Angel Island, first at Stuart Point and Point Knox. Col. René Edward De Russy was the Chief Engineer, James Terry Gardiner was the engineer tasked with designing and supervising the work. The Army established a camp on the island, and it became an infantry garrison during the US campaigns against Native American peoples in the West. In the 19th century, the designated the entire island as Fort McDowell and developed further facilities there.
A quarantine station was opened in Ayala Cove in 1891, during the Spanish–American War the island served as a discharge depot for returning troops. It continued to serve as a transit station throughout the first half of the 20th century, at the end of World War I the disembarkation center was commanded by William P. Burnham, who had commanded the 82nd Division in France during the war. In 1938, hearings concerning charges of membership in a political party against labor leader Harry Bridges were held on Angel Island before Dean James Landis of Harvard Law School. After eleven weeks of testimony that filled nearly 8,500 pages, the decision was accepted by the United States Department of Labor and Bridges was freed
Fort Point, San Francisco
Fort Point is a masonry seacoast fortification located at the southern side of the Golden Gate at the entrance to San Francisco Bay. This fort was completed just before the American Civil War by the United States Army, the fort is now protected as Fort Point National Historic Site, a United States National Historic Site administered by the National Park Service as a unit of the Golden Gate National Recreation Area. In 1769 Spain occupied the San Francisco area and by 1776 had established the areas first European settlement, with a mission and a presidio. To protect against encroachment by the British and Russians, Spain fortified the high white cliff at the narrowest part of the bays entrance, the Castillo de San Joaquin, built in 1794, was an adobe structure housing nine to thirteen cannons. Mexico won independence from Spain in 1821, gaining control of the region and the fort, following the United States victory in 1848, California was annexed by the U. S. and became a state in 1850. The gold rush of 1849 had caused rapid settlement of the area, military officials soon recommended a series of fortifications to secure San Francisco Bay.
Coastal defenses were built at Alcatraz Island, Fort Mason, the U. S. Army Corps of Engineers began work on Fort Point in 1853. Plans specified that the lowest tier of artillery be as close as possible to water level so cannonballs could ricochet across the surface to hit enemy ships at the water-line. Workers blasted the 90-foot cliff down to 15 feet above sea level, the structure featured seven-foot-thick walls and multi-tiered casemated construction typical of Third System forts. It was sited to defend the maximum amount of harbor area, while there were more than 30 such forts on the East Coast, Fort Point was the only one on the West Coast. In 1854 Inspector General Joseph K. Mansfield declared this point as the key to the whole Pacific Coast. a crew of 200, many unemployed miners, labored for eight years on the fort. In 1861, with war looming, the army mounted the forts first cannon, colonel Albert Sidney Johnston, commander of the Department of the Pacific, prepared Bay Area defenses and ordered in the first troops to the fort.
Kentucky-born Johnston resigned his commission to join the Confederate Army, throughout the Civil War, artillerymen at Fort Point stood guard for an enemy that never came. Troops soon moved out of Fort Point, and it was never again occupied by the army. The fort was important enough to receive protection from the elements. In 1869 a granite seawall was completed, the following year, some of the forts cannon were moved to Battery East on the bluffs nearby, where they were more protected. In 1882 Fort Point was officially named Fort Winfield Scott after the hero from the war against Mexico. The name never caught on and was applied to an artillery post at the Presidio
Sequoia National Park
Sequoia National Park is a national park in the southern Sierra Nevada east of Visalia, California, in the United States. It was established on September 25,1890, the park is south of and contiguous with Kings Canyon National Park, the two are administered by the National Park Service together as the Sequoia and Kings Canyon National Parks. They were designated the UNESCO Sequoia-Kings Canyon Biosphere Reserve in 1976, the park is famous for its giant sequoia trees, including the General Sherman tree, the largest tree on Earth. The General Sherman tree grows in the Giant Forest, which five out of the ten largest trees in the world. The Giant Forest is connected by the Generals Highway to Kings Canyon National Parks General Grant Grove, the parks giant sequoia forests are part of 202,430 acres of old-growth forests shared by Sequoia and Kings Canyon National Parks. Indeed, the preserve a landscape that still resembles the southern Sierra Nevada before Euro-American settlement. Many park visitors enter Sequoia National Park through its entrance near the town of Three Rivers at Ash Mountain at 1,700 ft elevation.
The last California grizzly was killed in this park in 1922, the California Black Oak is a key transition species between the chaparral and higher elevation conifer forest. At higher elevations in the front country, between 5,500 and 9,000 feet in elevation, the landscape becomes montane forest-dominated coniferous belt, found here are Ponderosa, Jeffrey and lodgepole pine trees, as well as abundant white and red fir. Found here too are the giant sequoia trees, the most massive living single-stem trees on earth, between the trees and summer snowmelts sometimes fan out to form lush, though delicate, meadows. In this region, visitors often see deer, Douglas squirrels, and American black bears. There are plans to reintroduce the bighorn sheep to this park, the vast majority of the park is roadless wilderness, no road crosses the Sierra Nevada within the parks boundaries. 84 percent of Sequoia and Kings Canyon National Parks is designated wilderness and is only by foot or by horseback. Sequoias backcountry offers a vast expanse of high-alpine wonders, covering the highest-elevation region of the High Sierra, the backcountry includes Mount Whitney on the eastern border of the park, accessible from the Giant Forest via the High Sierra Trail.
On the floor of canyon, at least two days hike from the nearest road, is the Kern Canyon hot spring, a popular resting point for weary backpackers. From the floor of Kern Canyon, the trail ascends again over 8,000 ft to the summit of Mount Whitney, in the summertime, Native Americans would travel over the high mountain passes to trade with tribes to the East. By the time the first European settlers arrived in the area, smallpox had spread to the region. The first European settler to homestead in the area was Hale Tharp, Tharp allowed his cattle to graze the meadow, but at the same time had a respect for the grandeur of the forest and led early battles against logging in the area
Border Field State Park
Border Field State Park is a state park of California, United States, containing beach and coastal habitat on the Mexico–United States border. The park is within the city limits of Imperial Beach in San Diego County and it is the southernmost point in the state of California. Immediately adjacent is the monument marking the Initial Point of Boundary Between U. S. the Treaty of Guadalupe Hidalgo was concluded on February 2,1848, officially ending the war between the United States and Mexico. It provided that the new border between the two countries be established by a joint United States and Mexican Boundary Survey. The commission began its survey at Border Field, the Tijuana River National Estuarine Research Reserve contains much of Border Field State Park and is an important wildlife habitat. The salt and freshwater marshes give refuge to migrating waterfowl and resident wading birds, such as black-necked stilt, American avocet, green-winged teal, American wigeon, the park offers hiking, horse trails, surf fishing and birding.
For fiscal year 2014-1561,799 people visited the Border Field State Park, small portions of the park often become flooded and are inaccessible to the public. New border fences have taken small portions of the park away, abandoned & Little-Known Airfields, California - Southern San Diego area
Lava Beds National Monument
Lava Beds National Monument is located in northeastern California, in Siskiyou and Modoc counties. The Monument lies on the flank of the Medicine Lake Volcano. The region in and around Lava Beds Monument lies at the junction of the Sierra-Klamath, the Monument was established as a United States National Monument on November 21,1925, and includes more than 46,000 acres. Lava Beds National Monument has numerous lava tube caves, with twenty-five having marked entrances and developed trails for public access, the monument offers trails through the high Great Basin xeric shrubland desert landscape and the volcanic field. 1872–1873, this area was the site of the Modoc War, the area of Captain Jacks Stronghold was named in his honor. Volcanic eruptions on the Medicine Lake shield volcano have created a rugged landscape punctuated by these many landforms of volcanism. Cinder cones are formed when magma is under great pressure and it is released in a fountain of lava, blown into the air from a central vent.
The lava cools as it falls, forming cinders that pile up around the vent, when the pressure has been relieved, the rest of the lava flows from the base of the cone. Cinder cones typically only erupt once, the cinder cones of Hippo Butte, Three Sisters, Juniper Butte, and Crescent Butte are all older than the Mammoth and Modoc Crater flows, more than 30, 000–40,000 years old. Eagle Nest Butte and Bearpaw Butte are 114,000 years old, Schonchin Butte cinder cone and the andesitic flow from its base were formed around 62,000 years ago. The flow that formed Valentine Cave erupted 10,850 years ago, an eruption that formed The Castles is younger than the Mammoth Crater flows. Even younger were eruptions from Fleener Chimneys, such as the Devils Homestead flow,10,500 years ago, about 1,110 years ago, plus or minus 60 years, the Callahan flow was produced by an eruption from Cinder Butte. Though Cinder Butte is just outside the boundary of the monument, spatter cones are built out of thicker lava. The lava is thrown out of the vent and builds, layer by layer, Fleener Chimneys and Black Crater are examples of spatter cones.
Roughly ninety percent of the lava in the Lava Beds Monument is basaltic, there are primarily two kinds of basaltic lava flows, pahoehoe and aa. Pahoehoe is smooth, often ropy and is the most common type of lava in Lava Beds, aa is formed when pahoehoe cools and loses some of its gases. Aa is rough and jagged, an excellent example is the Devils Homestead lava flow, most of the rest of the lava in the monument is andesitic. Pumice, a type of lava, is found covering the monument
Joshua Tree National Park
Joshua Tree National Park is located in southeastern California. Declared a U. S. National Park in 1994 when the U. S. Congress passed the California Desert Protection Act and it is named for the Joshua trees native to the park. It covers a area of 790,636 acres —an area slightly larger than the state of Rhode Island. A large part of the park, some 429,690 acres, is a wilderness area. The Little San Bernardino Mountains run through the southwest edge of the park, in 1950, the size of the park was reduced by about 265,000 acres to exclude some mining property. The park was elevated to a National Park on 31 October 1994 by the Desert Protection Act, the higher and cooler Mojave Desert is the special habitat of Yucca brevifolia, the Joshua tree for which the park is named. It occurs in patterns from dense forests to distantly spaced specimens, in addition to Joshua tree forests, the western part of the park includes some of the most interesting geologic displays found in Californias deserts. The dominant geologic features of landscape are hills of bare rock.
These hills are popular amongst rock climbing and scrambling enthusiasts, the flatland between these hills is sparsely forested with Joshua trees. Together with the piles and Skull Rock, the trees make the landscape otherworldly. Temperatures are most comfortable in the spring and fall, with an average high/low of 85 and 50 °F respectively, winter brings cooler days, around 60 °F, and freezing nights. It occasionally snows at higher elevations, summers are hot, over 100 °F during the day and not cooling much below 75 °F until the early hours of the morning. Joshua trees dominate the open spaces of the park, but in among the outcroppings are piñon pine, California juniper, Quercus turbinella, Quercus john-tuckeri. These communities are under stress, however, as the climate was wetter until the 1930s, with the same hot. These cycles were nothing new, but the vegetation did not prosper when wetter cycles returned. The difference may have been human development, cattle grazing took out some of the natural cover and made it less resistant to the changes.
But the bigger problem seems to be invasive species, such as cheatgrass, in drier times, they die back, but do not quickly decompose. This makes wildfires hotter and more destructive, which some of the trees that would have otherwise survived
Golden Gate National Recreation Area
The Golden Gate National Recreation Area is a U. S. National Recreation Area protecting 80,002 acres of ecologically and historically significant landscapes surrounding the San Francisco Bay Area. Much of the park is land used by the United States Army. GGNRA is managed by the National Park Service and is one of the most visited units of the National Park system in the United States, with more than 15 million visitors a year. It is one of the largest urban parks in the world, the park is not one continuous locale, but rather a collection of areas that stretch from southern San Mateo County to northern Marin County, and includes several areas of San Francisco. The park is as diverse as it is expansive, it contains famous tourist attractions such as Muir Woods National Monument, the park was created thanks to the cooperative legislative efforts of cosponsors Congressman William S. Mailliard and Congressman Phillip Burton. In 1972, President Richard Nixon signed into law An Act to Establish the Golden Gate National Recreation Area, the bill allocated $120 million for land acquisition and development.
The National Park Service first purchased Alcatraz and Fort Mason from the U. S. Army, the Nature Conservancy transferred the land to the GGNRA. These properties formed the basis for the park. Throughout the next 30 years, the National Park service acquired land and historic sites from the U. S. Army, private landowners and corporations, incorporating them into the GGNRA. Many decommissioned Army bases and fortifications were incorporated into the park, including Fort Funston, four Nike missile sites, The Presidio, the latest acquisition by the National Park Service is Mori Point, a small parcel of land on the Pacifica coast. In 1988, UNESCO designated the GGNRA and 12 adjacent protected areas the Golden Gate Biosphere Reserve, the property, located south of Pacifica and surrounding the communities of Moss Beach and Montara, is home to many diverse plant and animal species. The bill passed in the Senate, but did not pass the House of Representatives, Fort Baker - former Army post located on the northern side of the Golden Gate Headlands Center for the Arts - an artist residency program set in renovated military buildings in the Marin Headlands.
Nike Missile Site SF-88 - a decommissioned Army surface-to-air missile site located near Fort Barry, located at the southwestern corner of the Presidio Battery Chamberlin - one of the last remaining coastal defense disappearing guns on the U. S. Trails lead across the ridge and to Sharp Park beach, the site includes recently restored wetlands and a pond, protecting endangered San Francisco garter snake and red-legged frog habitat. Rancho Corral de Tierra - the GGNRAs newest park, Golden Gate National Recreation Area Scenery Video, a video showing the scenery observed from the GGNRA, including footage from Lands End
Yosemite National Park
Yosemite National Park is a national park spanning portions of Tuolumne and Madera counties in Northern California. The park, which is managed by the National Park Service, on average, about 4 million people visit Yosemite each year, and most spend the majority of their time in the seven square miles of Yosemite Valley. The park set a record in 2016, surpassing 5 million visitors for the first time in its history. Almost 95% of the park is designated wilderness, Yosemite was central to the development of the national park idea. First, Galen Clark and others lobbied to protect Yosemite Valley from development, Yosemite is one of the largest and least fragmented habitat blocks in the Sierra Nevada, and the park supports a diversity of plants and animals. The park has a range from 2,127 to 13,114 feet and contains five major vegetation zones, chaparral/oak woodland, lower montane forest, upper montane forest, subalpine zone. Of Californias 7,000 plant species, about 50% occur in the Sierra Nevada, there is suitable habitat for more than 160 rare plants in the park, with rare local geologic formations and unique soils characterizing the restricted ranges many of these plants occupy.
The geology of the Yosemite area is characterized by granitic rocks, about 10 million years ago, the Sierra Nevada was uplifted and tilted to form its relatively gentle western slopes and the more dramatic eastern slopes. The uplift increased the steepness of stream and river beds, resulting in formation of deep, about one million years ago and ice accumulated, forming glaciers at the higher alpine meadows that moved down the river valleys. Ice thickness in Yosemite Valley may have reached 4,000 feet during the early glacial episode, the downslope movement of the ice masses cut and sculpted the U-shaped valley that attracts so many visitors to its scenic vistas today. The name Yosemite originally referred to the name of a tribe which was driven out of the area by the Mariposa Battalion. Before the area was called Ahwahnee by indigenous people, as revealed by archeological finds, the Yosemite Valley has been inhabited for nearly 3,000 years, though humans may have first visited the area as long as 8,000 to 10,000 years ago.
The indigenous natives called themselves the Ahwahneechee, meaning dwellers in Ahwahnee and they are related to the Northern Paiute and Mono tribes. Many tribes visited the area to trade, including nearby Central Sierra Miwoks, a major trading route went over Mono Pass and through Bloody Canyon to Mono Lake, just to the east of the Yosemite area. Vegetation and game in the region were similar to that present today, acorns were a staple to their diet, as well as seeds and plants, salmon. In 1851 as part of the Mariposa Wars intended to suppress Native American resistance and he was pursuing forces of around 200 Ahwahneechee led by Chief Tenaya. Accounts from this battalion were the first well-documented reports of ethnic Europeans entering Yosemite Valley, attached to Savages unit was Dr. Lafayette Bunnell, the company physician, who wrote about his awestruck impressions of the valley in The Discovery of the Yosemite. Bunnell is credited with naming Yosemite Valley, based on his interviews with Chief Tenaya, Bunnell wrote that Chief Tenaya was the founder of the Pai-Ute Colony of Ah-wah-nee
Anza-Borrego Desert State Park
Anza-Borrego Desert State Park is a state park located within the Colorado Desert of southern California, United States. The park takes its name from 18th century Spanish explorer Juan Bautista de Anza and borrego, the Spanish word for bighorn sheep. With 600,000 acres that includes one-fifth of San Diego County, ABDSP is the largest state park in California and, after New Yorks Adirondack Park, the second largest in the contiguous United States. The park occupies eastern San Diego County and reaches into Imperial and Riverside counties, ABDSP is around a two-hour drive northeast from San Diego, southeast from Riverside or Irvine, and south from Palm Springs. The park is an anchor in the Mojave and Colorado Deserts Biosphere Reserve, Park information and maps, interpretive events and displays and listening devices for the hearing impaired are all available in the Visitor Center. ABDSP has Wi-Fi access to the Internet in various sections of the park, many visitors approach ABDSP from the east-Coachella Valley side via California County Route S22 and S78.
These highways climb from the coast to 2,400 ft above sea level, the great bowl of the surrounding desert is surrounded by mountains, with the Vallecito Mountains to the south and the highest Santa Rosa Mountains to the north. They are in the wilderness area, without paved roads. In January of 2017 Anza-Borrego Desert State Park was named the best state park in California, the habitats of ABDSP are primarily within the Colorado Desert ecosystem of the Sonoran Desert ecoregion. The higher extreme northern and eastern sections in the Peninsular Ranges are in the California montane chaparral, the park features and desert washes, rock formations and colorful badlands, vast arid landscapes, and dramatic mountains. The bajadas are predominantly creosote bush-bur sage with creosote bush and the palo verde-cactus shrub ecosystems with the palo verde tree, cacti, in the washes, Colorado/Sonoran microphylla woodlands can be found. These woodlands include such plants as tree, velvet mesquite. ABDSP has natural springs and oases, with the only native palm.
Seasonal wildflower displays can be stunning in any plant community association throughout the park, the high-country to the north and east has closed-cone pine forests and oak woodlands. The oases are prolific with all types of fauna, especially for bird-watching, in the reptile class, desert iguanas and the red diamond rattlesnakes can be seen — with caution. ===Desert bighorn sheep=== Some areas of ABDSP are habitat for the Peninsular bighorn sheep, few park visitors see them, and the sheep are justly wary. A patient few observers each year see and count this endangered species to study the population, the expanses of ABDSPs eroded badlands provide a different view into the regions long-vanished tropical past. The inland of southeastern California was not always a desert, the study of the fossilized remains of ancient life, is the key to understanding this prehistoric world