Blue Ridge Mountains
The Blue Ridge Mountains are a physiographic province of the larger Appalachian Mountains range. The mountain range is located in the eastern United States, extends 550 miles southwest from southern Pennsylvania through Maryland, West Virginia, North Carolina, South Carolina and Georgia; this province consists of northern and southern physiographic regions, which divide near the Roanoke River gap. To the west of the Blue Ridge, between it and the bulk of the Appalachians, lies the Great Appalachian Valley, bordered on the west by the Ridge and Valley province of the Appalachian range; the Blue Ridge Mountains are noted for having a bluish color. Trees put the "blue" in Blue Ridge, from the isoprene released into the atmosphere, thereby contributing to the characteristic haze on the mountains and their distinctive color. Within the Blue Ridge province are two major national parks – the Shenandoah National Park in the northern section, the Great Smoky Mountains National Park in the southern section – and eight national forests including George Washington and Jefferson National Forests, Cherokee National Forest, Pisgah National Forest, Nantahala National Forest and Chattahoochee National Forest.
The Blue Ridge contains the Blue Ridge Parkway, a 469-mile long scenic highway that connects the two parks and is located along the ridge crest-lines with the Appalachian Trail. Although the term "Blue Ridge" is sometimes applied to the eastern edge or front range of the Appalachian Mountains, the geological definition of the Blue Ridge province extends westward to the Ridge and Valley area, encompassing the Great Smoky Mountains, the Great Balsams, the Roans, the Blacks, the Brushy Mountains and other mountain ranges; the Blue Ridge extends as far north into Pennsylvania as South Mountain. While South Mountain dwindles to mere hills between Gettysburg and Harrisburg, the band of ancient rocks that form the core of the Blue Ridge continues northeast through the New Jersey and Hudson River highlands reaching The Berkshires of Massachusetts and the Green Mountains of Vermont; the Blue Ridge contains the highest mountains in eastern North America south of Baffin Island. About 125 peaks exceed 5,000 feet in elevation.
The highest peak in the Blue Ridge is Mt. Mitchell in North Carolina at 6,684 feet. There are 39 peaks in North Tennessee higher than 6,000 feet. Southern Sixers is a term used by peak baggers for this group of mountains; the Blue Ridge Parkway runs 469 miles along crests of the Southern Appalachians and links two national parks: Shenandoah and Great Smoky Mountains. In many places along the parkway, there are metamorphic rocks with folded bands of light-and dark-colored minerals, which sometimes look like the folds and swirls in a marble cake. Most of the rocks that form the Blue Ridge Mountains are ancient granitic charnockites, metamorphosed volcanic formations, sedimentary limestone. Recent studies completed by Richard Tollo, a professor and geologist at George Washington University, provide greater insight into the petrologic and geochronologic history of the Blue Ridge basement suites. Modern studies have found that the basement geology of the Blue Ridge is made of compositionally unique gneisses and granitoids, including orthopyroxene-bearing charockites.
Analysis of zircon minerals in the granite completed by John Aleinikoff at the U. S. Geological Survey has provided more detailed emplacement ages. Many of the features found in the Blue Ridge and documented by Tollo and others have confirmed that the rocks exhibit many similar features in other North American Grenville-age terranes; the lack of a calc-alkaline affinity and zircon ages less than 1,200 Ma suggest that the Blue Ridge is distinct from the Adirondacks, Green Mountains, the New York-New Jersey Highlands. The petrologic and geochronologic data suggest that the Blue Ridge basement is a composite orogenic crust, emplaced during several episodes from a crustal magma source. Field relationships further illustrate that rocks emplaced prior to 1,078–1,064 Ma preserve deformational features; those emplaced post-1,064 Ma have a massive texture and missed the main episode of Mesoproterozoic compression. The Blue Ridge Mountains began forming during the Silurian Period over 400 million years ago.
320 Mya, North America, Europe collided, pushing up the Blue Ridge. At the time of their emergence, the Blue Ridge were among the highest mountains in the world and reached heights comparable to the much younger Alps. Today, due to weathering and erosion over hundreds of millions of years, the highest peak in the range, Mount Mitchell in North Carolina, is only 6,684 feet high – still the highest peak east of the Rockies; the English who settled colonial Virginia in the early 17th century recorded that the native Powhatan name for the Blue Ridge was Quirank. At the foot of the Blue Ridge, various tribes including the Siouan Manahoacs, the Iroquois, the Shawnee hunted and fished. A German physician-explorer, John Lederer, first reached the crest of the Blue Ridge in 1669 and again the following year. At the Treaty of Albany negotiated by Lieutenant Governor Alexander Spotswood, of Virginia with the Iroquois between 1718 and 1722, the Iroquois ceded lands they had conquered south of the Potomac River and east of the Blue Ridge to the Virginia Colony.
This treaty made the Blue Ridge the new demarcation point between the areas and tribes subject to the Six Nati
Biodiversity refers to the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic and ecosystem level. Terrestrial biodiversity is greater near the equator, the result of the warm climate and high primary productivity. Biodiversity is not distributed evenly on Earth, is richest in the tropics; these tropical forest ecosystems cover less than 10 percent of earth's surface, contain about 90 percent of the world's species. Marine biodiversity is highest along coasts in the Western Pacific, where sea surface temperature is highest, in the mid-latitudinal band in all oceans. There are latitudinal gradients in species diversity. Biodiversity tends to cluster in hotspots, has been increasing through time, but will be to slow in the future. Rapid environmental changes cause mass extinctions. More than 99.9 percent of all species that lived on Earth, amounting to over five billion species, are estimated to be extinct. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described.
More in May 2016, scientists reported that 1 trillion species are estimated to be on Earth with only one-thousandth of one percent described. The total amount of related DNA base pairs on Earth is estimated at 5.0 x 1037 and weighs 50 billion tonnes. In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC. In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor of all organisms living on Earth; the age of the Earth is about 4.54 billion years. The earliest undisputed evidence of life on Earth dates at least from 3.5 billion years ago, during the Eoarchean Era after a geological crust started to solidify following the earlier molten Hadean Eon. There are microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia. Other early physical evidence of a biogenic substance is graphite in 3.7 billion-year-old meta-sedimentary rocks discovered in Western Greenland. More in 2015, "remains of biotic life" were found in 4.1 billion-year-old rocks in Western Australia.
According to one of the researchers, "If life arose quickly on Earth.. it could be common in the universe."Since life began on Earth, five major mass extinctions and several minor events have led to large and sudden drops in biodiversity. The Phanerozoic eon marked a rapid growth in biodiversity via the Cambrian explosion—a period during which the majority of multicellular phyla first appeared; the next 400 million years included repeated, massive biodiversity losses classified as mass extinction events. In the Carboniferous, rainforest collapse led to a great loss of animal life; the Permian–Triassic extinction event, 251 million years ago, was the worst. The most recent, the Cretaceous–Paleogene extinction event, occurred 65 million years ago and has attracted more attention than others because it resulted in the extinction of the dinosaurs; the period since the emergence of humans has displayed an ongoing biodiversity reduction and an accompanying loss of genetic diversity. Named the Holocene extinction, the reduction is caused by human impacts habitat destruction.
Conversely, biodiversity positively impacts human health in a number of ways, although a few negative effects are studied. The United Nations designated 2011–2020 as the United Nations Decade on Biodiversity. 1916 - The term biological diversity was used first by J. Arthur Harris in "The Variable Desert," Scientific American, JSTOR 6182: "The bare statement that the region contains a flora rich in genera and species and of diverse geographic origin or affinity is inadequate as a description of its real biological diversity." 1975 - The term natural diversity was introduced 1980 - Thomas Lovejoy introduced the term biological diversity to the scientific community in a book.. It became used. 1985 -The contracted form biodiversity was coined by W. G. Rosen 1985 - The term "biodiversity" appears in the article, "A New Plan to Conserve the Earth's Biota" by Laura Tangley. 1988 - The term biodiversity first appeared in a publication. The present - the term has achieved widespread use. "Biodiversity" is most used to replace the more defined and long established terms, species diversity and species richness.
Biologists most define biodiversity as the "totality of genes and ecosystems of a region". An advantage of this definition is that it seems to describe most circumstances and presents a unified view of the traditional types of biological variety identified: taxonomic diversity ecological diversity morphological diversity functional diversity This multilevel construct is consistent with Datman and Lovejoy. An explicit definition consistent with this interpretation was first given in a paper by Bruce A. Wilcox commissioned by the International Union for the Conservation of Nature and Natural Resources for the 1982 World National Parks Conference. Wilcox's definition was "Biological diversity is the variety of life forms...at all levels of biologi
Bats are mammals of the order Chiroptera. Bats are more manoeuvrable than birds, flying with their long spread-out digits covered with a thin membrane or patagium; the smallest bat, arguably the smallest extant mammal, is Kitti's hog-nosed bat, 29–34 mm in length, 15 cm across the wings and 2–2.6 g in mass. The largest bats are the flying foxes and the giant golden-crowned flying fox, Acerodon jubatus, which can weigh 1.6 kg and have a wingspan of 1.7 m. The second largest order of mammals, bats comprise about 20% of all classified mammal species worldwide, with over 1,200 species; these were traditionally divided into two suborders: the fruit-eating megabats, the echolocating microbats. But more recent evidence has supported dividing the order into Yinpterochiroptera and Yangochiroptera, with megabats as members of the former along with several species of microbats. Many bats are insectivores, most of the rest are frugivores. A few species feed on animals other than insects. Most bats are nocturnal, many roost in caves or other refuges.
Bats are present throughout the world, with the exception of cold regions. They are important in their ecosystems for dispersing seeds. Bats provide humans at the cost of some threats. Bat dung has been used as fertiliser. Bats consume insect pests, they are sometimes numerous enough to serve as tourist attractions, are used as food across Asia and the Pacific Rim. They are natural reservoirs such as rabies. In many cultures, bats are popularly associated with darkness, witchcraft and death. An older English name for bats is flittermouse, which matches their name in other Germanic languages, related to the fluttering of wings. Middle English had bakke, most cognate with Old Swedish natbakka, which may have undergone a shift from -k- to -t- influenced by Latin blatta, "moth, nocturnal insect"; the word "bat" was first used in the early 1570s. The name "Chiroptera" derives from Ancient Greek: χείρ – cheir, "hand" and πτερόν – pteron, "wing"; the delicate skeletons of bats do not fossilise well, it is estimated that only 12% of bat genera that lived have been found in the fossil record.
Most of the oldest known bat fossils were very similar to modern microbats, such as Archaeopteropus. The extinct bats Palaeochiropteryx tupaiodon and Hassianycteris kumari are the first fossil mammals whose colouration has been discovered: both were reddish-brown. Bats were grouped in the superorder Archonta, along with the treeshrews and primates. Modern genetic evidence now places bats in the superorder Laurasiatheria, with its sister taxon as Fereuungulata, which includes carnivorans, odd-toed ungulates, even-toed ungulates, cetaceans. One study places Chiroptera as a sister taxon to odd-toed ungulates; the phylogenetic relationships of the different groups of bats have been the subject of much debate. The traditional subdivision into Megachiroptera and Microchiroptera reflected the view that these groups of bats had evolved independently of each other for a long time, from a common ancestor capable of flight; this hypothesis recognised differences between microbats and megabats and acknowledged that flight has only evolved once in mammals.
Most molecular biological evidence supports the view that bats form a monophyletic group. Genetic evidence indicates that megabats originated during the early Eocene, belong within the four major lines of microbats. Two new suborders have been proposed. Yangochiroptera includes the other families of a conclusion supported by a 2005 DNA study. A 2013 phylogenomic study supported the two new proposed suborders. In the 1980s, a hypothesis based on morphological evidence stated the Megachiroptera evolved flight separately from the Microchiroptera; the flying primate hypothesis proposed that, when adaptations to flight are removed, the Megachiroptera are allied to primates by anatomical features not shared with Microchiroptera. For example, the brains of megabats have advanced characteristics. Although recent genetic studies support the monophyly of bats, debate continues about the meaning of the genetic and morphological evidence; the 2003 discovery of an early fossil bat from the 52 million year old Green River Formation, Onychonycteris finneyi, indicates that flight evolved before echolocative abilities.
Onychonycteris had claws on all five of its fingers, whereas modern bats have at most two claws on two digits of each hand. It had longer hind legs and shorter forearms, similar to climbing mammals that hang under branches, such as sloths and gibbons; this palm-sized bat had short, broad wings, suggesting that it could not fly as fast or as far as bat species. Instead of flapping its wings continuously while flying, Onychonycteris alternated between flaps and
Guilford Courthouse National Military Park
Guilford Courthouse National Military Park, at 2332 New Garden Road in Greensboro, Guilford County, North Carolina, commemorates the Battle of Guilford Court House, fought on March 15, 1781. This battle opened the campaign; the losses by the British in this battle contributed to their surrender at Yorktown seven months later. The battlefield is operated by the National Park Service. Based on research of historical evidence, the interpretation of the battle has changed since the late 20th century, which will affect the placement of monuments and markers. In 1886, local resident David Schenck initiated plans to gain control of land to commemorate the Guilford Courthouse battleground as a park; the following year, he chartered the non-profit Guilford Battle Ground Company to advance such efforts. From an early date, he planned on the group's donating the property it purchased to the federal government; when the US Congress established Guilford Courthouse as a national military park in 1917, the GBGC turned over its 125 acres at no charge.
Without David Schenck's generosity, it is possible that the park would not exist today. Although generous in starting the park, the years of control by the GBGC left a mixed legacy. First, Schenck did not preserve the terrain in its approximate historical state, but beautified the landscape for a pleasing experience. Before the grounds were established as a military park, state historical societies began to erect monuments in the area purchased by the GBGC. Although well-meant, these monuments and interpretations were not based on researched evidence and were constructed in convenient, if inaccurate, locations. Second, he adopted an interpretation of the battle that encompassed a much smaller area than is indicated by contemporary accounts. Historians believe his limited funds, coupled with landowners' demanding top dollar, influenced his interpretation; this mis-led historical groups who relied on his work. It hampered government efforts to acquire land or resist development in areas outside the original area designated as battleground by Schenck.
Since his time, the expanding city of Greensboro approached and encircled the park with private development, destroying some battlefield areas. When the National Park Service assumed responsibility for the park, their historians and researchers sought to clarify the accuracy of the locations of the battle; the renewed accuracy places many of the monuments in locations that had little reference to the actual battle. Today, the National Park Service has moved beyond Schenck's interpretation of the battle with a more researched understanding of the battle's events, it hopes to reconstruct its monuments to be consistent with historical evidence. A revived Guilford Battleground Company supports preservation efforts for Guilford Courthouse National Military Park and Colonial Heritage Center, where British forces assembled for their advance; the park is linked by a bicycle path to the adjoining Greensboro Country Park, residents use both for jogging and cycling. The military park was established on March 2, 1917.
It was transferred from the War Department to the National Park Service August 10, 1933. As with all historic areas administered by the National Park Service, the military park was listed on the National Register of Historic Places in 1966, when it was established; the park's nomination was updated in 1996, in 2001 it was designated a National Historic Landmark. Battle of Guilford Court House Guilford Court House, North Carolina Hoskins House Historic District List of National Historic Landmarks in North Carolina National Register of Historic Places listings in Guilford County, North Carolina The National Parks: Index 2001-2003. Washington: U. S. Department of the Interior. Redeemed From Oblivion: An Administrative History of Guilford Courthouse National Military Park. Washington: U. S. Department of the Interior. Guilford Courthouse National Military Park, Official Website, National Park Service "Virtual Tour", Guilford Courthouse Military Park, National Park Service Guilford Courthouse: A Pivotal Battle in the War for Independence, a National Park Service Teaching with Historic Places lesson plan "Guilford Battleground Company", Official Website for supporters of the park
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. While these definitions may seem adequate, when looked at more they represent problematic species concepts. For example, the boundaries between related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, in a ring species. Among organisms that reproduce only asexually, the concept of a reproductive species breaks down, each clone is a microspecies. All species are given a two-part name, a "binomial"; the first part of a binomial is the genus.
The second part is called the specific epithet. For example, Boa constrictor is one of four species of the genus Boa. None of these is satisfactory definitions, but scientists and conservationists need a species definition which allows them to work, regardless of the theoretical difficulties. If species were fixed and distinct from one another, there would be no problem, but evolutionary processes cause species to change continually, to grade into one another. Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped. Charles Darwin's 1859 book The Origin of Species explained how species could arise by natural selection; that understanding was extended in the 20th century through genetics and population ecology. Genetic variability arises from mutations and recombination, while organisms themselves are mobile, leading to geographical isolation and genetic drift with varying selection pressures.
Genes can sometimes be exchanged between species by horizontal gene transfer. Viruses are a special case, driven by a balance of mutation and selection, can be treated as quasispecies. Biologists and taxonomists have made many attempts to define species, beginning from morphology and moving towards genetics. Early taxonomists such as Linnaeus had no option but to describe what they saw: this was formalised as the typological or morphological species concept. Ernst Mayr emphasised reproductive isolation, but this, like other species concepts, is hard or impossible to test. Biologists have tried to refine Mayr's definition with the recognition and cohesion concepts, among others. Many of the concepts are quite similar or overlap, so they are not easy to count: the biologist R. L. Mayden recorded about 24 concepts, the philosopher of science John Wilkins counted 26. Wilkins further grouped the species concepts into seven basic kinds of concepts: agamospecies for asexual organisms biospecies for reproductively isolated sexual organisms ecospecies based on ecological niches evolutionary species based on lineage genetic species based on gene pool morphospecies based on form or phenotype and taxonomic species, a species as determined by a taxonomist.
A typological species is a group of organisms in which individuals conform to certain fixed properties, so that pre-literate people recognise the same taxon as do modern taxonomists. The clusters of variations or phenotypes within specimens would differentiate the species; this method was used as a "classical" method of determining species, such as with Linnaeus early in evolutionary theory. However, different phenotypes are not different species. Species named in this manner are called morphospecies. In the 1970s, Robert R. Sokal, Theodore J. Crovello and Peter Sneath proposed a variation on this, a phenetic species, defined as a set of organisms with a similar phenotype to each other, but a different phenotype from other sets of organisms, it differs from the morphological species concept in including a numerical measure of distance or similarity to cluster entities based on multivariate comparisons of a reasonably large number of phenotypic traits. A mate-recognition species is a group of sexually reproducing organisms that recognize one another as potential mates.
Expanding on this to allow for post-mating isolation, a cohesion species is the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms. A further development of the recognition concept is provided by the biosemiotic concept of species. In microbiology, genes can move even between distantly related bacteria extending to the whole bacterial domain; as a rule of thumb, microbiologists have assumed that kinds of Bacteria or Archaea with 16S ribosomal RNA gene sequences more similar than 97% to each other need to be checked by DNA-DNA hybridisation to decide if they belong to the same species or not. This concept was narrowed in 2006 to a similarity of 98.7%. DNA-DNA hybri
Salamanders are a group of amphibians characterized by a lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, the presence of a tail in both larvae and adults. All present-day salamander families are grouped together under the order Urodela. Salamander diversity is most abundant in the Northern Hemisphere and most species are found in the Holarctic ecozone, with some species present in the Neotropical zone. Salamanders have more than four toes on their front legs and five on their rear legs, but some species have fewer digits and others lack hind limbs, their permeable skin makes them reliant on habitats in or near water or other cool, damp places. Some salamander species are aquatic throughout their lives, some take to the water intermittently, others are terrestrial as adults, they are capable of regenerating lost limbs, as well as other damaged parts of their bodies. Researchers hope to reverse engineer the remarkable regenerative processes for potential human medical applications, such as brain and spinal cord injury treatment or preventing harmful scarring during heart surgery recovery.
Members of the family Salamandridae are known as newts and lack the costal grooves along the sides of their bodies typical of other groups. The skin of some species contains the powerful poison tetrodotoxin. Salamanders lay eggs in water and have aquatic larvae, but great variation occurs in their lifecycles; some species in harsh environments reproduce while still in the larval state. The skin lacks scales and is moist and smooth to the touch, except in newts of the Salamandridae, which may have velvety or warty skin, wet to the touch; the skin may be drab or brightly colored, exhibiting various patterns of stripes, spots, blotches, or dots. Male newts become colored during the breeding season. Cave species dwelling in darkness lack pigmentation and have a translucent pink or pearlescent appearance. Salamanders range in size from the minute salamanders, with a total length of 2.7 cm, including the tail, to the Chinese giant salamander which reaches 1.8 m and weighs up to 65 kg. Most, are between 10 and 20 cm in length.
An adult salamander resembles a small lizard, having a basal tetrapod body form with a cylindrical trunk, four limbs, a long tail. Except in the family Salamandridae, the head and tail have a number of vertical depressions in the surface which run from the mid-dorsal region to the ventral area and are known as costal grooves, their function seems to be to help keep the skin moist by channeling water over the surface of the body. Some aquatic species, such as sirens and amphiumas, have reduced or absent hind limbs, giving them an eel-like appearance, but in most species, the front and rear limbs are about the same length and project sidewards raising the trunk off the ground; the feet are broad with short digits four on the front feet and five on the rear. Salamanders do not have claws, the shape of the foot varies according to the animal's habitat. Climbing species have elongated, square-tipped toes, while rock-dwellers have larger feet with short, blunt toes; the tree-climbing salamander has plate-like webbed feet which adhere to smooth surfaces by suction, while the rock-climbing Hydromantes species from California have feet with fleshy webs and short digits and use their tails as an extra limb.
When ascending, the tail props up the rear of the body, while one hind foot moves forward and swings to the other side to provide support as the other hind foot advances. In larvae and aquatic salamanders, the tail is laterally flattened, has dorsal and ventral fins, undulates from side to side to propel the animal through the water. In the families Ambystomatidae and Salamandridae, the male's tail, larger than that of the female, is used during the amplexus embrace to propel the mating couple to a secluded location. In terrestrial species, the tail moves to counterbalance the animal as it runs, while in the arboreal salamander and other tree-climbing species, it is prehensile; the tail is used by certain plethodontid salamanders that can jump, to help launch themselves into the air. The tail is used as a storage organ for proteins and lipids, it functions as a defense against predation, when it may be lashed at the attacker or autotomised when grabbed. Unlike frogs, an adult salamander is able to regenerate its tail when these are lost.
The skin of salamanders, in common with other amphibians, is thin, permeable to water, serves as a respiratory membrane, is well-supplied with glands. It has cornified outer layers, renewed periodically through a skin shedding process controlled by hormones from the pituitary and thyroid glands. During moulting, the skin breaks around the mouth, the animal moves forwards through the gap to shed the skin; when the front limbs have been worked clear, a series of body ripples pushes the skin towards the rear. The hind limbs are extracted and push the skin farther back, before it is freed by friction as the salamander moves forward with the tail pressed against the ground; the animal then eats the resulting sloughed skin. Glands in the skin discharge mucus which keeps the skin moist, an important factor in skin respiration and thermoregulation; the sticky layer helps protect against bacterial infections and molds, reduces friction when swimming, makes the animal slippery and more difficult for predators to catch.
Granular glands scattered on the upper surface the head and tail, produce repel
National Historic Site (United States)
National Historic Site is a designation for an recognized area of national historic significance in the United States. An NHS contains a single historical feature directly associated with its subject. A related but separate designation, the National Historical Park, is an area that extends beyond single properties or buildings, its resources include a mix of historic and sometimes significant natural features; as of 2018, there are 89 NHSs. Most NHPs and NHSs are managed by the National Park Service; some federally designated sites are owned by local authorities or owned, but are authorized to request assistance from the NPS as affiliated areas. One property, Grey Towers National Historic Site, is managed by the U. S. Forest Service; as of October 15, 1966, all historic areas, including NHPs and NHSs, in the NPS are automatically listed on the National Register of Historic Places. There are about 90,000 NRHP sites, the large majority of which are neither owned nor managed by the NPS. Of these, about 2,500 have been designated at the highest status as National Historic Landmark sites.
National Historic Sites are federally owned and administered properties, though some remain under private or local government ownership. There are 89 NHSs, of which 77 are official NPS units, 11 are NPS affiliated areas, 1 is managed by the US Forest Service. Derived from the Historic Sites Act of 1935, a number of NHSs were established by United States Secretaries of the Interior, but most have been authorized by acts of Congress. In 1937, the first NHS was created in Salem, Massachusetts in order to preserve and interpret the maritime history of New England and the United States. There is one International Historic Site in the US park system, a unique designation given to Saint Croix Island, Maine, on the New Brunswick border; the title, given to the site of the first permanent French settlement in America, recognizes the influence that has had on both Canada and the United States. The NPS does not distinguish among these designations in terms of their preservation or management policies. In the United States, sites are "historic", while parks are "historical".
The NPS explains that a site can be intrinsically historic, while a park is a modern legal invention. As such, a park is not itself "historic", but can be called "historical" when it contains historic resources, it is the resources. Klondike Gold Rush International Historical Park was formally established in 1998 by the United States and Canada, the year of the centennial of the gold rush the park commemorates; the park comprises Klondike Gold Rush National Historical Park in Washington and Alaska, Chilkoot Trail National Historic Site in British Columbia. It was this trail which so many prospectors took in hopes of making their fortunes in the Klondike River district of Yukon. National Historic Sites List of World Heritage Sites in North America Designation of National Park System Units