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43-614: Custer County School District is nestled between the Wet Mountains and Sangre de Cristo Mountains of south central Colorado. It includes the neighboring towns of Silver Cliff and Westcliffe, with a county-wide population of 3,500. All students are in the same building but have three sections within the school. There are 114 students enrolled in Custer County High School and 349 in the district. The school operates Monday to Thursday, from 8am to 4pm. The average class size at

86-605: A cataclysm known as " The Great Dying ", the third and most severe Phanerozoic mass extinction. The early Cambrian climate was probably moderate at first, becoming warmer over the course of the Cambrian, as the second-greatest sustained sea level rise in the Phanerozoic got underway. However, as if to offset this trend, Gondwana moved south, so that, in Ordovician time, most of West Gondwana (Africa and South America) lay directly over

129-445: A foothold on land. These early plants were the forerunners of all plant life on land. During this time, there were four continents: Gondwana (Africa, South America, Australia, Antarctica, Siberia), Laurentia (North America), Baltica (Northern Europe), and Avalonia (Western Europe). The recent rise in sea levels allowed many new species to thrive in water. The Devonian spanned from 419–359 million years ago. Also known as "The Age of

172-450: A wide range of sediments and environments, which aids correlation between different sites around the world. Trace fossils reflect the complexity of the body plan of the organism that made them. Ediacaran trace fossils are simple, sub-horizontal feeding traces. As more complex organisms evolved, their more complex behaviour was reflected in greater diversity and complexity of the trace fossils they left behind. After two decades of deliberation,

215-659: Is considered the first Phanerozoic mass extinction event, and the second deadliest. The Silurian spanned from 444–419 million years ago. The Silurian saw the rejuvenation of life as the Earth recovered from the previous glaciation. This period saw the mass evolution of fish, as jawless fish became more numerous, jawed fish evolved, and the first freshwater fish evolved, though arthropods, such as sea scorpions , were still apex predators . Fully terrestrial life evolved, including early arachnids, fungi, and centipedes. The evolution of vascular plants ( Cooksonia ) allowed plants to gain

258-558: Is derived from the Greek palaiós (παλαιός, "old") and zōḗ (ζωή, "life") meaning "ancient life". The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion , in which most modern phyla first appeared. Arthropods , molluscs , fish , amphibians , reptiles , and synapsids all evolved during

301-473: Is now a ghost town after a period of gold and silver mining over the past two centuries. The summit of SH 96 in Hardscrabble Canyon has no official name, but is known locally as Hardscrabble Pass , elevation 9085 ft (2769 m). Its broad saddle is just east of Silver Cliff. The summit of SH 165 is Bigelow Divide , elevation 9403 ft (2866 m), near Ophir Creek Campground. The intersection of

344-570: Is the sudden appearance of nearly all of the invertebrate animal phyla in great abundance at the beginning of the Cambrian. The first vertebrates appeared in the form of primitive fish, which greatly diversified in the Silurian and Devonian Periods. The first animals to venture onto dry land were the arthropods. Some fish had lungs, and powerful bony fins that in the late Devonian, 367.5 million years ago, allowed them to crawl onto land. The bones in their fins eventually evolved into legs and they became

387-537: The Appalachians , Caledonides , Ural Mountains , and mountains of Tasmania . The Cambrian spanned from 539–485 million years ago and is the first period of the Paleozoic Era of the Phanerozoic. The Cambrian marked a boom in evolution in an event known as the Cambrian explosion in which the largest number of creatures evolved in any single period of the history of the Earth. Creatures like algae evolved, but

430-518: The Carboniferous Rainforest Collapse . Gondwana was glaciated as much of it was situated around the south pole. The Permian spanned from 299–252 million years ago and was the last period of the Paleozoic Era. At the beginning of this period, all continents joined together to form the supercontinent Pangaea, which was encircled by one ocean called Panthalassa . The land mass was very dry during this time, with harsh seasons, as

473-628: The Early Palaeozoic Icehouse , culminating in the Hirnantian glaciation, 445  million years ago at the end of the Ordovician. The middle Paleozoic was a time of considerable stability. Sea levels had dropped coincident with the ice age, but slowly recovered over the course of the Silurian and Devonian. The slow merger of Baltica and Laurentia, and the northward movement of bits and pieces of Gondwana created numerous new regions of relatively warm, shallow sea floor. As plants took hold on

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516-565: The South Pole . The early Paleozoic climate was strongly zonal, with the result that the "climate", in an abstract sense, became warmer, but the living space of most organisms of the time – the continental shelf marine environment – became steadily colder. However, Baltica (Northern Europe and Russia) and Laurentia (eastern North America and Greenland) remained in the tropical zone, while China and Australia lay in waters which were at least temperate. The early Paleozoic ended, rather abruptly, with

559-662: The Wet Mountain Valley . The highest point is known as Greenhorn Mountain , which has multiple peaks, the highest of which reaches 12,346 feet (3,763 m). Greenhorn Peak, St. Charles Peak, and North Peak all reach above tree line . Most of the Wet Mountains are within the San Isabel National Forest . To the west the adjacent Wet Mountain Valley contains the small towns of Westcliffe and Silver Cliff . Within

602-634: The Fish", the Devonian featured a huge diversification of fish, including armored fish like Dunkleosteus and lobe-finned fish which eventually evolved into the first tetrapods. On land, plant groups diversified rapidly in an event known as the Devonian explosion when plants made lignin , leading to taller growth and vascular tissue; the first trees and seeds evolved. These new habitats led to greater arthropod diversification. The first amphibians appeared and fish occupied

645-630: The ICS chose Fortune Head , Burin Peninsula, Newfoundland as the basal Cambrian Global Stratotype Section and Point (GSSP) at the base of the Treptichnus pedum assemblage of trace fossils and immediately above the last occurrence of the Ediacaran problematica fossils Harlaniella podolica and Palaeopsacichnus . The base of the Phanerozoic, Paleozoic and Cambrian is dated at 538.8+/-0.2 Ma and now lies below both

688-585: The Middle Carboniferous). An important evolutionary development of the time was the evolution of amniotic eggs , which allowed amphibians to move farther inland and remain the dominant vertebrates for the duration of this period. Also, the first reptiles and synapsids evolved in the swamps. Throughout the Carboniferous, there was a cooling trend, which led to the Permo-Carboniferous glaciation or

731-618: The Palaeozoic had very few facultatively motile animals that could easily adjust to disturbance, with such creatures composing 1% of its assemblages in contrast to 50% in Cenozoic faunal assemblages. Non-motile animals untethered to the substrate, extremely rare in the Cenozoic, were abundant in the Palaeozoic. Palaeozoic phytoplankton overall were both nutrient-poor themselves and adapted to nutrient-poor environmental conditions. This phytoplankton nutrient poverty has been cited as an explanation for

774-604: The Paleozoic and Neoproterozoic eras and the Ediacaran and Cambrian periods. When Adam Sedgwick named the Paleozoic in 1835, he defined the base as the first appearance of complex life in the rock record as shown by the presence of trilobite -dominated fauna. Since then evidence of complex life in older rock sequences has increased and by the second half of the 20th century, the first appearance of small shelly fauna (SSF), also known as early skeletal fossils, were considered markers for

817-546: The Paleozoic informally into early and late sub-eras: the Early Paleozoic consisting of the Cambrian, Ordovician and Silurian; the Late Paleozoic consisting of the Devonian, Carboniferous and Permian. The name Paleozoic was first used by Adam Sedgwick (1785–1873) in 1838 to describe the Cambrian and Ordovician periods. It was redefined by John Phillips (1800–1874) in 1840 to cover the Cambrian to Permian periods. It

860-410: The Paleozoic. Life began in the ocean but eventually transitioned onto land, and by the late Paleozoic, great forests of primitive plants covered the continents, many of which formed the coal beds of Europe and eastern North America . Towards the end of the era, large, sophisticated synapsids and diapsids were dominant and the first modern plants ( conifers ) appeared. The Paleozoic Era ended with

903-522: The Silurian Period, about 420 million years ago, when they began to transition onto dry land. Terrestrial flora reached its climax in the Carboniferous, when towering lycopsid rainforests dominated the tropical belt of Euramerica . Climate change caused the Carboniferous Rainforest Collapse which fragmented this habitat, diminishing the diversity of plant life in the late Carboniferous and Permian periods. A noteworthy feature of Paleozoic life

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946-517: The Wet Mountains are within Custer County , stretching into Fremont County to the north, Huerfano County to the south, and Pueblo County to the east. The range runs approximately north to south from U.S. Highway 50 to Walsenburg a distance of more than 40 miles (64 km). The range is up to about 12 miles (19 km) wide and is bordered on the east by the Great Plains and on the west by

989-488: The base of the Paleozoic. However, whilst SSF are well preserved in carbonate sediments, the majority of Ediacaran to Cambrian rock sequences are composed of siliciclastic rocks where skeletal fossils are rarely preserved. This led the International Commission on Stratigraphy (ICS) to use trace fossils as an indicator of complex life. Unlike later in the fossil record, Cambrian trace fossils are preserved in

1032-509: The boundary confine its age to a narrow range of 251.902+/-0.024 Ma. The beginning of the Paleozoic Era witnessed the breakup of the supercontinent of Pannotia and ended while the supercontinent Pangaea was assembling. The breakup of Pannotia began with the opening of the Iapetus Ocean and other Cambrian seas and coincided with a dramatic rise in sea level. Paleoclimatic studies and evidence of glaciers indicate that Central Africa

1075-561: The climate of the interior of Pangaea was not regulated by large bodies of water. Diapsids and synapsids flourished in the new dry climate. Creatures such as Dimetrodon and Edaphosaurus ruled the new continent. The first conifers evolved, and dominated the terrestrial landscape. Near the end of the Permian, however, Pangaea grew drier. The interior was desert, and new taxa such as Scutosaurus and Gorgonopsids filled it. Eventually they disappeared, along with 95% of all life on Earth, in

1118-561: The continental margins, oxygen levels increased and carbon dioxide dropped, although much less dramatically. The north–south temperature gradient also seems to have moderated, or metazoan life simply became hardier, or both. At any event, the far southern continental margins of Antarctica and West Gondwana became increasingly less barren. The Devonian ended with a series of turnover pulses which killed off much of middle Paleozoic vertebrate life, without noticeably reducing species diversity overall. There are many unanswered questions about

1161-507: The empty continent of Gondwana. By the end of the Ordovician, Gondwana was at the south pole, early North America had collided with Europe, closing the intervening ocean. Glaciation of Africa resulted in a major drop in sea level, killing off all life that had established along coastal Gondwana. Glaciation may have caused the Ordovician–Silurian extinction events , in which 60% of marine invertebrates and 25% of families became extinct, and

1204-560: The end of the Permian period. In late middle Permian the pareiasaurs originated, successful herbivores and the only sauropsids that could reach sizes comparable to some of the largest synapsids. The Palaeozoic marine fauna was notably lacking in predators relative to the present day. Predators made up about 4% of the fauna in Palaeozoic assemblages while making up 17% of temperate Cenozoic assemblages and 31% of tropical ones. Infaunal animals made up 4% of soft substrate Palaeozoic communities but about 47% of Cenozoic communities. Additionally,

1247-692: The equivalent level is marked by the disappearance of the Permian Dicynodon tetrapods . This means events previously considered to mark the Permian-Triassic boundary, such as the eruption of the Siberian Traps flood basalts , the onset of greenhouse climate, ocean anoxia and acidification and the resulting mass extinction are now regarded as being of latest Permian in age. The GSSP is near Meishan , Zhejiang Province, southern China. Radiometric dating of volcanic clay layers just above and below

1290-418: The first appearance of trilobites and SSF. The boundary between the Paleozoic and Mesozoic eras and the Permian and Triassic periods is marked by the first occurrence of the conodont Hindeodus parvus . This is the first biostratigraphic event found worldwide that is associated with the beginning of the recovery following the end- Permian mass extinctions and environmental changes. In non-marine strata,

1333-653: The first of three geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma at the start of the Mesozoic Era. The Paleozoic is subdivided into six geologic periods (from oldest to youngest), Cambrian , Ordovician , Silurian , Devonian , Carboniferous and Permian . Some geological timescales divide

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1376-461: The first tetrapods, 390  million years ago , and began to develop lungs. Amphibians were the dominant tetrapods until the mid-Carboniferous, when climate change greatly reduced their diversity, allowing amniotes to take over. Amniotes would split into two clades shortly after their origin in the Carboniferous; the synapsids, which was the dominant group, and the sauropsids . The synapsids continued to prosper and increase in number and variety till

1419-660: The largest extinction event of the Phanerozoic Eon , the Permian–Triassic extinction event . The effects of this catastrophe were so devastating that it took life on land 30 million years into the Mesozoic Era to recover. Recovery of life in the sea may have been much faster. The base of the Paleozoic is one of the major divisions in geological time representing the divide between the Proterozoic and Phanerozoic eons,

1462-540: The late Paleozoic. The Mississippian (early Carboniferous Period) began with a spike in atmospheric oxygen, while carbon dioxide plummeted to new lows. This destabilized the climate and led to one, and perhaps two, ice ages during the Carboniferous. These were far more severe than the brief Late Ordovician ice age; but, this time, the effects on world biota were inconsequential. By the Cisuralian Epoch, both oxygen and carbon dioxide had recovered to more normal levels. On

1505-603: The most ubiquitous of that period were the armored arthropods, like trilobites. Almost all marine phyla evolved in this period. During this time, the supercontinent Pannotia begins to break up, most of which later became the supercontinent Gondwana. The Ordovician spanned from 485–444 million years ago. The Ordovician was a time in Earth's history in which many of the biological classes still prevalent today evolved, such as primitive fish, cephalopods, and coral. The most common forms of life, however, were trilobites, snails and shellfish. The first arthropods went ashore to colonize

1548-406: The mountains, Highway 96 weaves its way down to Wetmore by way of Hardscrabble Canyon and is one of only three main exits from the valley. The only other highway in the range is Highway 165 , which travels through the range to Rye and Colorado City , and can also be noted for Lake Isabel and Bishop's Castle . Other towns/communities in the small range include Beulah and Rosita , which

1591-512: The other hand, the assembly of Pangaea created huge arid inland areas subject to temperature extremes. The Lopingian Epoch is associated with falling sea levels, increased carbon dioxide and general climatic deterioration, culminating in the devastation of the Permian extinction. While macroscopic plant life appeared early in the Paleozoic Era and possibly late in the Neoproterozoic Era of the earlier eon, plants mostly remained aquatic until

1634-593: The school is around 12. This Colorado school-related article is a stub . You can help Misplaced Pages by expanding it . Wet Mountains The Wet Mountains are a small mountain range in southern Colorado , named for the amount of snow they receive in the winter as compared to the dry Great Plains to the east. They are a sub-range of the Sangre de Cristo Mountains , in the southern Rocky Mountains System. There are three variant names of mountain range: Cuerno Verde , Greenhorn Mountains , and Sierra Mojada . Most of

1677-472: The short, but apparently severe, late Ordovician ice age. This cold spell caused the second-greatest mass extinction of the Phanerozoic Eon. Over time, the warmer weather moved into the Paleozoic Era. The Ordovician and Silurian were warm greenhouse periods, with the highest sea levels of the Paleozoic (200 m above today's); the warm climate was interrupted only by a 30 million year cool period,

1720-459: The southern end and in the northwest. The range lies on the southeast end of the Central Colorado volcanic field and contains Eocene to Oligocene (38–29 Ma) volcanic rocks and carbonatites . Paleozoic The Paleozoic ( / ˌ p æ l i . ə ˈ z oʊ . ɪ k , - i . oʊ -, ˌ p eɪ -/ PAL-ee-ə-ZOH-ik , -⁠ee-oh- , PAY- ; or Palaeozoic ) Era is

1763-547: The top of the food chain. Earth's second Phanerozoic mass extinction event (a group of several smaller extinction events), the Late Devonian extinction , ended 70% of existing species. The Carboniferous is named after the large coal deposits laid down during the period. It spanned from 359–299 million years ago. During this time, average global temperatures were exceedingly high; the early Carboniferous averaged at about 20 degrees Celsius (but cooled to 10 °C during

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1806-445: The two highways, between Silver Cliff and Wetmore, is McKenzie Junction, elevation 8359 ft. The gravel road that connects SH 78 from Beulah to SH 165 is known locally as Bathtub Pass, for a discarded roadside clawfoot bathtub . The Wet Mountains are the east flank of an uplifted faulted anticline . The core of the range consists of Precambrian granitic rocks with Paleozoic and Mesozoic strata in fault contact around

1849-531: Was most likely in the polar regions during the early Paleozoic. The breakup of Pannotia was followed by the assembly of the huge continent Gondwana ( 510  million years ago ). By the mid-Paleozoic, the collision of North America and Europe produced the Acadian-Caledonian uplifts, and a subducting plate uplifted eastern Australia . By the late Paleozoic, continental collisions formed the supercontinent of Pangaea and created great mountain chains, including

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