Paleo-Indians , by
Heinrich Harder The first occupants of the
Mesa Verde region, which spans from southeastern Utah to northwestern New Mexico, were nomadic
Paleo-Indians who arrived in the area BC. They followed herds of big game and camped near rivers and streams, many of which dried up as the glaciers that once covered parts of the
San Juan Mountains receded. The earliest Paleo-Indians were the
Clovis culture and
Folsom tradition, defined largely by how they fashioned
projectile points. Although they left evidence of their presence throughout the region, there is little indication that they lived in central Mesa Verde during this time. After 9600 BC, the area's environment grew warmer and drier, a change that brought to central Mesa Verde pine forests and the animals that thrive in them. Paleo-Indians began inhabiting the mesa in increasing numbers , though it is unclear whether they were seasonal occupants or year-round residents. Development of the
atlatl during this period made it easier for them to hunt smaller game, a crucial advance at a time when most of the region's big game had disappeared from the landscape.
Archaic , BC, Sego Canyon, Utah 6000 BC marks the beginning of the
Archaic period in North America. Archaeologists differ as to the origin of the Mesa Verde Archaic population; some believe they developed exclusively from local Paleo-Indians, called the Foothills Mountain Complex, but others suggest that the variety of projectile points found in Mesa Verde indicates influence from surrounding areas, including the
Great Basin, the
San Juan Basin, and the
Rio Grande Valley. The Archaic people probably developed locally, but were also influenced by contact, trade, and intermarriage with immigrants from these outlying areas. The early Archaic people living near Mesa Verde utilized the atlatl and harvested a wider variety of plants and animals than the Paleo-Indians had while retaining their primarily nomadic lifestyle. They inhabited the outlying areas of the Mesa Verde region, but also the mountains, mesa tops, and canyons, where they created rock shelters and
rock art, and left evidence of animal processing and
chert knapping. Environmental stability during the period drove population expansion and migration. Major warming and drying from 5000 to 2500 might have led middle Archaic people to seek the cooler climate of Mesa Verde, whose higher elevation brought increased snowpack that, when coupled with spring rains, provided relatively plentiful amounts of water. By the late Archaic, more people were living in semi-permanent rock shelters that preserved perishable goods such as baskets, sandals, and mats. They started to make a variety of twig figurines that usually resembled sheep or deer. The late Archaic is marked by increased trade in exotic materials such as
obsidian and
turquoise. Marine shells and
abalone from the Pacific coast made their way to Mesa Verde from Arizona, and the Archaic people worked them into necklaces and pendants. Rock art flourished, and people lived in rudimentary houses made of mud and wood. Their early attempts at plant domestication eventually developed into the sustained agriculture that marked the end of the Archaic period, .
Basketmaker culture With the introduction of corn to the Mesa Verde region BC and the trend away from nomadism toward permanent
pithouse settlements, the Archaic Puebloan transitioned into what archaeologists call the
Basketmaker culture.
Basketmaker II people are characterized by their combination of foraging and farming skills, use of the
atlatl, and creation of finely woven baskets in the absence of earthen pottery. By 300, corn had become the preeminent staple of the Basketmaker II people's diet, which relied less and less on wild food sources and more on domesticated crops. In addition to the fine basketry for which they were named, Basketmaker II people fashioned a variety of household items from plant and animal materials, including sandals, robes, pouches, mats, and blankets. They also made clay pipes and gaming pieces. Basketmaker men were relatively short and muscular, averaging less than tall. Their skeletal remains reveal signs of hard labor and extensive travel, including degenerative joint disease, healed fractures, and moderate anemia associated with iron deficiency. They buried their dead near or amongst their settlements, and often included luxury items as gifts, which might indicate differences in relative social status. Basketmaker II people are also known for their distinctive rock art, which can be found throughout Mesa Verde. They depicted animals and people, in both abstract and realistic forms, in single works and more elaborate panels. A common subject was the hunchbacked flute player that the
Hopi call
Kokopelli. By 500 AD, atlatls were being supplanted by the bow and arrow and baskets by pottery, marking the end of the Basketmaker II Era and the beginning of the
Basketmaker III Era. Ceramic vessels were a major improvement over
pitch-lined baskets, gourds, and animal hide containers, which had been the primary water storage containers in the region. Pottery also protected seeds against mold, insects, and rodents. By 600, Ancestral Pueblo People were using clay pots to cook soups and stews. Year-round settlements first appear around this time. The population of the San Juan Basin increased markedly after 575, when there were very few Basketmaker III sites in Mesa Verde; by the early 7th century, there were many such sites in the mesa. For the next 150 years, villages typically consisted of small groups of one to three residences. The population of Mesa Verde was approximately 1,000 to 1,500 people. Beans and new varieties of corn were introduced to the region . By 775, some settlements had grown to accommodate more than one hundred people; the construction of large, above-ground storage buildings began around this time. Basketmakers endeavored to store enough food for their family for one year, but also retained residential mobility so they could quickly relocate their dwellings in the event of resource depletion or consistently inadequate crop yields. By the end of the 8th century, the smaller hamlets, which were typically occupied for ten to forty years, had been supplanted by larger ones that saw continuous occupation for as many as two generations. Basketmaker III people established a tradition of holding large ceremonial gatherings near community pit structures.
Ancestral Puebloans Pueblo I: 750 to 900 750 marks the end of the Basketmaker III Era and the beginning of the Pueblo I period. The transition is characterized by major changes in the design and construction of buildings and the organization of household activities. Pueblo I people doubled their capacity for food storage from one year to two and built interconnected, year-round residences called
pueblos. Many household activities that had previously been reserved for subterranean pit-houses were moved to these above-ground dwellings. This altered the function of pit-houses from all-purpose spaces to ones used primarily for community ceremonies, although they continued to house large extended families, particularly during winter months. During the late 8th century, Pueblo people began building square pit structures that archaeologists call proto
kivas. They were typically deep and wide. The first pueblos appeared at Mesa Verde sometime after 650; by 850 more than half of Pueblo people lived in them. As local populations grew, Puebloans found it difficult to survive on hunting, foraging, and gardening, which made them increasingly reliant on domesticated corn. This shift from semi-nomadism to a "sedentary and communal way of life changed ancestral Pueblo society forever". Within a generation the average number of households in these settlements grew from 1–3 to 15–20, with average populations of two hundred people. Population density increased dramatically, with as many as a dozen families occupying roughly the same space that had formerly housed two. This brought increased security against raids and encouraged greater cooperation amongst residents. It also facilitated trade and intermarriage between clans, and by the late 8th century, as Mesa Verde's population was being augmented by settlers from the south, four distinct cultural groups occupied the same villages. Large Pueblo I settlements laid claim to the resources found within . They were typically organized in groups of at least three and spaced about apart. By 860, there were approximately 8,000 people living in Mesa Verde. Within the plazas of larger villages, the Pueblo I people dug massive pit structures of that became central gathering places. These structures represent early architectural expressions of what would eventually develop into the
Pueblo II Era great houses of
Chaco Canyon. Despite robust growth during the early and mid-9th century, unpredictable rainfall and periodic drought led to a dramatic reversal of settlement trends in the area. Many late Pueblo I villages were abandoned after less than forty years of occupation, and by 880 Mesa Verde's population was in steady decline. The beginning of the 10th century saw widespread depopulation of the region, as people emigrated south of the
San Juan River to Chaco Canyon in search of reliable rains for farming. As Pueblo people migrated south, to where many of their ancestors had emigrated two hundred years before, the influence of Chaco Canyon grew, and by 950 Chaco had supplanted Mesa Verde as the region's cultural center.
Pueblo II: 900 to 1150 The Pueblo II Period is marked by the growth and outreach of communities centered around the great houses of Chaco Canyon. Despite their participation in the vast Chacoan system, Puebloan retained a distinct cultural identity while melding regional innovation with ancient tradition, inspiring further architectural advancements; the 9th century Puebloan pueblos influenced two hundred years of Chacoan great house construction. Droughts during the late 9th century rendered Ancestral Pueblo people's dry land farming unreliable, which led to their growing crops only near drainages for the next 150 years. Crop yields returned to healthy levels by the early 11th century. By 1050 the population of the area began to rebound; as agricultural prosperity increased, people immigrated to Mesa Verde from the south. Pueblonan farmers increasingly relied on masonry reservoirs during the Pueblo II Era. During the 11th century, they built
check dams and terraces near drainages and slopes in an effort to conserve soil and runoff. These fields offset the danger of crop failures in the larger dry land fields. By the mid-10th and early 11th centuries, protokivas had evolved into smaller circular structures called kivas, which were usually across. These Mesa Verde-style kivas included a feature from earlier times called a
sipapu, which is a hole dug in the north of the chamber and symbolizes the Ancestral Puebloan's place of emergence from the underworld. At this time, Ancestral Pueblo people began to move away from the post and mud
jacal-style buildings that marked the Pueblo I Period toward masonry construction, which had been utilized in the region as early as 700, but was not widespread until the 11th and 12th centuries. The expansion of Chacoan influence in the Mesa Verde area left its most visible mark in the form of Chaco-style masonry great houses that became the focal point of many Puebloan villages after 1075. Far View House, the largest of these, is considered a classic Chaco "outlier", on which construction likely began between 1075 and 1125, although some archaeologists argue that it was begun as early as 1020. The era's timber and earth unit pueblos were typically inhabited for about twenty years. During the early 12th century, the locus of regional control shifted away from Chaco to
Aztec, New Mexico, in the southern Mesa Verde region. By 1150, drought had once again stressed the region's inhabitants, leading to a temporary cessation of great house construction at Mesa Verde.
Pueblo III: 1150 to 1300 A severe drought from 1130 to 1180 led to rapid depopulation in many parts of the San Juan Basin, particularly at Chaco Canyon. As the extensive Chacoan system collapsed, people increasingly migrated to Mesa Verde, causing major population growth in the area. This led to much larger settlements of six to eight hundred people, which reduced mobility for the Puebloan, who had in the past frequently relocated their dwellings and fields as part of their agriculture strategy. In order to sustain these larger populations, they dedicated more and more of their labor to farming. Population increases also led to expanded tree felling that reduced habitat for many wild plant and animal species that the Puebloan had relied on, further deepening their dependency on domesticated crops that were susceptible to drought-related failure. A recent study has shown that residents resorted to cannibalism starting in 1150 due to the discovery of disarticulated human remains that were prepared and consumed. The Chacoan system brought large quantities of imported goods to Mesa Verde during the late 11th and early 12th centuries, including pottery, shells, and turquoise, but by the late 12th century, as the system collapsed, the amount of goods imported by the mesa quickly declined, and Mesa Verde became isolated from the surrounding region. For approximately six hundred years, most Puebloan farmers had lived in small, mesa-top homesteads of one or two families. They were typically located near their fields and walking distance to sources of water. This practice continued into the mid- to late 12th century, but by the start of the 13th century they began living in canyon locations that were close to water sources and within walking distance of their fields. Ancestral Pueblo villages thrived during the mid-Pueblo III Era, when architects constructed massive, multi-story buildings, and artisans adorned pottery with increasingly elaborate designs. Structures built during this period have been described as "among the world's greatest archaeological treasures". Pueblo III masonry buildings were typically occupied for approximately fifty years, more than double the usable lifespan of the Pueblo II jacal structures. Others were continuously inhabited for two hundred years or more. Architectural innovations such as towers and multi-walled structures also appear during the Pueblo III Era. Mesa Verde's population remained fairly stable during the 12th century drought. At the start of the 13th century, approximately 22,000 people lived there. The area saw moderate population increases during the following decades, and dramatic ones from 1225 to 1260. Most of the people in the region lived in the plains west of the mesa at locations such as
Yellow Jacket Pueblo, near Cortez, Colorado. Others colonized canyon rims and slopes in multi-family structures that grew to unprecedented size as populations swelled. By 1260, the majority of Puebloans lived in large pueblos that housed several families and more than one hundred people. The 13th century saw 69 years of below average rainfall in the Mesa Verde region, and after 1270 the area suffered from especially cold temperatures.
Dendrochronology indicates that the last tree felled for construction on the mesa was cut in 1281. There was a major decline in
ceramic imports to the region during this time, but local production remained steady. Despite challenging conditions, the Puebloans continued to farm the area until a severely dry period from 1276 to 1299 ended seven hundred years of continuous human occupation at Mesa Verde. Archaeologists refer to this period as the "Great Drought". The last inhabitants of the mesa left the area .
Warfare During the Pueblo III period (1150 to 1300), Puebloans built numerous stone masonry towers that likely served as defensive structures. They often incorporated hidden tunnels connecting the towers to associated kivas. Warfare was conducted using the same tools the Puebloans used for hunting game, including bows and arrows, stone axes, and wooden clubs and spears. They also crafted hide and basket shields that were used only during battles. Periodic warfare occurred on the mesa throughout the 13th century. Civic leaders in the region likely attained power and prestige by distributing food during times of drought. This system probably broke down during the "Great Drought", leading to intense warfare between competing clans. Increasing economic and social uncertainty during the century's final decades led to widespread conflict. Evidence of partly burned villages and post-mortem trauma have been uncovered, and the residents of one village appear to have been the victims of a site-wide massacre. Evidence of violence and
cannibalism has been documented in the central Mesa Verde region. While most of the violence, which peaked between 1275 and 1285, is generally ascribed to in-fighting amongst Puebloans, archaeological evidence found at Sand Canyon Pueblo, in
Canyons of the Ancients National Monument, suggests that violent interactions also occurred between Puebloans and people from outside the region. Evidence of the attacks was discovered by members of the
Crow Canyon Archaeological Center during the 1990s. The assaults, which also occurred at the national monument's Castle Rock Pueblo, were dated to , and are considered to have effectively ended several centuries of Puebloan occupation at those sites. Many of the victims showed signs of skull fractures, and the uniformity of the injuries suggest that most were inflicted with a small stone axe. Others were
scalped, dismembered, and cannibalized. The anthropophagy (cannibalism) might have been undertaken as a survival strategy during times of starvation. The archaeological record indicates that, rather than being isolated to the Mesa Verde region, violent conflict was widespread in North America during the late 13th and early 14th centuries, and was likely exacerbated by global climate changes that negatively affected food supplies throughout the continent.
Migration The Mesa Verde region saw unusually cold and dry conditions during the beginning of the 13th century. This might have driven emigration to Mesa Verde from less hospitable locations. The added population stressed the mesa's environment, further straining an agricultural society that was suffering from drought. The region's bimodal precipitation pattern, which brought rainfall during spring and summer and snowfall during autumn and winter, began to fail post-1250. After 1260, there was a rapid depopulation of Mesa Verde, as "tens of thousands of people" emigrated or died from starvation. Many smaller communities in the Four Corners region were also abandoned during this period. The Ancestral Puebloans had a long history of migration in the face of environmental instability, but the depopulation of Mesa Verde at the end of the 13th century was different in that the region was almost completely emptied, and no descendants returned to build permanent settlements. While drought, resource depletion, and overpopulation all contributed to instability during the last two centuries of Ancestral Puebloan occupation, their overdependence on maize crops is considered the "fatal flaw" of their subsistence strategy. The vacating Ancestral Pueblo people left almost no direct evidence of their migration, but they left behind household goods, including cooking utensils, tools, and clothing, which gave archaeologists the impression that the emigration was haphazard or hurried. An estimated 20,000 people lived in the region during the 13th century, but by the start of the 14th century the area was nearly uninhabited. Many surviving emigrants may have relocated to southern Arizona and New Mexico. Although the rate of settlement is unclear, increases in sparsely populated areas, such as
Rio Chama,
Pajarito Plateau, and Santa Fe, correspond directly with the period of migration from Mesa Verde. Archaeologists believe the Puebloans who settled in the areas near the Rio Grande, where Mesa Verde black-on-white pottery became widespread during the 14th century, were likely related to the households they joined and not unwelcome intruders. Archaeologists view this migration as a continuation, versus a dissolution, of Ancestral Puebloan society and culture. Many others relocated to the banks of the
Little Colorado River, in western New Mexico and eastern Arizona. While archaeologists tend to focus on the
"push" factors that drove the Puebloans away from the region, there were also several environmental "pull factors", such as warmer temperatures, better farming conditions, plentiful timber, and
bison herds, which incentivized relocation to the area near the Rio Grande. In addition to numerous settlements along the Rio Grande, contemporary descendants of the Puebloans live in pueblos at
Acoma,
Zuni,
Jemez, and
Laguna.
Organization Although Chaco Canyon might have exerted regional control over Mesa Verde during the late 11th and early 12th centuries, most archaeologists view the Mesa Verde region as a collection of smaller communities based on central sites and related outliers that were never fully integrated into a larger civic structure. Several ancient roads, averaging wide and lined with earthen
berms, have been identified in the region. Most appear to connect communities and shrines; others encircle great house sites. The extent of the network is unclear, but no roads have been discovered leading to the Chacoan
Great North Road, or directly connecting Mesa Verde and Chacoan sites. Ancestral Puebloan shrines, called
herraduras, have been identified near road segments in the region. Their purpose is unclear, but several C-shaped herraduras have been excavated, and they are thought to have been "directional shrines" used to indicate the location of great houses.
Architecture /
National Park Service partnership. Since Fire Temple was at least partially built to conform to the dimensions of the cliff alcove in which it was built, it is neither round in form nor truly subterranean like other structures generally defined as
kivas. Mesa Verde is best known for a large number of well-preserved cliff dwellings, houses built in alcoves, or rock overhangs along the
canyon walls. The structures contained within these alcoves were mostly blocks of hard
sandstone, held together and plastered with
adobe mortar. Specific constructions had many similarities but were generally unique in form due to the individual topography of different alcoves along the canyon walls. In marked contrast to earlier constructions and villages on top of the mesas, the cliff dwellings of Mesa Verde reflected a region-wide trend towards the aggregation of growing regional populations into close, highly defensible quarters during the 13th century. Pueblo buildings were built with stone, windows facing south, and in
U, E and
L shapes. The buildings were located more closely together and reflected deepening religious celebration. Towers were built near kivas and likely used for lookouts. Pottery became more versatile, including pitchers, ladles, bowls, jars and dishware for food and drink. White pottery with black designs emerged, the pigments coming from plants. Water management and conservation techniques, including the use of reservoirs and silt-retaining dams, also emerged during this period. Styles for these sandstone/mortar constructions, both surface and cliff dwellings, included T-shaped windows and doors. This has been taken by some archaeologists, including Stephen H. Lekson, as evidence of the continuing reach of the Chacoan system. Other researchers see these elements as part of a more generalized Puebloan style or spiritual significance rather than evidence of a continuing specific elite socioeconomic system. While much of the construction in these sites is consistent with common Pueblo architectural forms, including kivas, towers, and
pit-houses, the space constrictions of these alcoves necessitated what seems to have been a far denser concentration of their populations. Mug House, a typical cliff dwelling of the period, was home to around 100 people who shared 94 small rooms and eight kivas built against each other and sharing many of their walls; builders in these areas maximized space in any way they could, with no areas considered off-limits to construction.
Astronomy The Pueblo people used astronomical observations to plan their farming and religious ceremonies, drawing on both natural features in the landscape and masonry structures built for this purpose. Several great houses in the region were aligned to the
cardinal directions, which positioned windows, doors, and walls along the path of the sun, whose rays would indicate the passing of seasons. Mesa Verde's Sun Temple is thought to have been an astronomical observatory. The temple is D-shaped, and its alignment is 10.7 degrees off true east–west. Its location and orientation indicate that its builders understood the cycles of both the sun and the moon. It is aligned to the major
lunar standstill, which occurs once every 18.6 years, and the sunset during the
winter solstice, which can be viewed setting over the temple from a platform at the south end of Cliff Palace, across Fewkes Canyon. At the bottom of the canyon is the Sun Temple fire pit, which is illuminated by the first rays of the rising sun during the winter solstice. Sun Temple is one of the largest exclusively ceremonial structures ever built by the Ancestral Puebloans.
Agriculture and water-control systems Starting in the 6th century, the farmers living in central Mesa Verde cultivated corn, beans, squash, and gourds. The combination of corn and beans provided the Puebloans with the amino acids of a
complete protein. When conditions were good, of land would provide enough food for a family of three or four individuals for one year, providing they supplemented with game and wild plants. As Puebloans increasingly relied on corn as a dietary staple, the success or failure of crop yields factored heavily into their lives. The mesa tilts slightly to the south, which increased its exposure to the sun. Before the introduction of pottery, foods were baked, roasted, and parched. Hot rocks dropped into containers could bring water to a brief boil, but because beans must be boiled for an hour or more their use was not widespread until after pottery had disseminated throughout the region. With the increased availability of ceramics after 600, beans became much easier to cook. This provided a high quality protein that reduced reliance on hunting. It also aided corn cultivation, as
legumes add much needed nutrients to soils they are grown in, which likely increased corn yields. Most Pueblo people practiced
dry farming, which relied on rain to water their crops, but others utilized runoff, springs,
seeps, and natural collection pools. Starting in the 9th century, they dug and maintained reservoirs that caught runoff from summer showers and spring snowmelt; some crops were watered by hand. Archaeologists believe that prior to the 13th century, springs and other sources of water were considered shared public resources, but as the Pueblo moved into increasingly larger pueblos built near or around water supplies control was privatized and limited to members of the surrounding community. Between 750 and 800, Puebloans began constructing two large water containment structures in canyon bottoms – the Morefield and Box Elder reservoirs. Soon afterward, work began on two more: the Far View and Sagebrush reservoirs, which were approximately across and constructed on the mesa top. The reservoirs lie on an east–west line that runs for approximately , which suggests builders followed a centralized plan for the system. In 2004, the
American Society of Civil Engineers designated these four structures as
National Civil Engineering Historic Landmarks. A 2014 geospatial analyses suggested that neither collection nor retention of water was possible in the Far View Reservoir. This interpretation views the structure as a ceremonial space with procession roads in an adaptation of Chacoan culture.
Hunting and foraging Puebloans typically harvested local small game, but sometimes organized hunting parties that traveled long distances. Their main sources of animal protein came from
mule deer and rabbits, but they occasionally hunted bighorn sheep, antelope, and elk. They began to domesticate turkeys starting around 1000, and by the 13th century consumption of the animal peaked, supplanting deer as the primary protein source at many sites. These domesticated turkeys consumed large amounts of corn, which further deepened reliance on the staple crop. Puebloans wove blankets from turkey feathers and rabbit fur, and made implements such as
awls and needles from turkey and deer bones. Despite the availability of fish in the area's rivers and streams, archaeological evidence suggests that they were rarely eaten. Puebloans supplemented their diet by gathering the seeds and fruits of wild plants, searching large expanses of land while procuring these resources. Depending on the season, they collected piñon nuts and juniper berries, weedy goosefoot, pigweed, purslane,
tomatillo,
tansy mustard,
globe mallow, sunflower seeds, and
yucca, as well as various species of grass and cacti.
Prickly pear fruits provided a rare source of natural sugar. Wild seeds were cooked and ground up into porridge. They used
sagebrush and
mountain mahogany, along with piñon and juniper, for firewood. They also smoked wild tobacco. Because the Ancestral Puebloans considered all material consumed and discarded by their communities as sacred, their
midden piles were viewed with reverence. Starting during the Basketmaker III period, , Puebloans often buried their dead in these mounds.
Pottery Scholars are divided as to whether pottery was invented in the Four Corners region or introduced from the south. Specimens of shallow, unfired clay bowls found at
Canyon de Chelly indicate the innovation might have been derived from using clay bowls to parch seeds. Repeated uses rendered these bowls hard and impervious to water, which might represent the first fired pottery in the region. An alternate theory suggests that pottery originated in the
Mogollon Rim area to the south, where brown-paste bowls were used during the first few centuries of the
common era. Others believe pottery was introduced to Mesa Verde from Mexico, CE. There is no evidence of ancient pottery markets in the region, but archaeologists believe that local potters exchanged decorative wares between families. Cooking pots made with crushed
igneous rock tempers from places like
Ute Mountain were more resilient and desirable, and Puebloans from throughout the region traded for them.
Neutron activation analysis indicates that much of the black-on-white pottery found at Mesa Verde was produced locally.
Cretaceous clays from both the
Dakota and
Menefee Formations were used in black-on-white wares, and Mancos Formation clays for corrugated jars. Evidence that pottery of both types moved between several locations around the region suggests interaction between groups of ancient potters, or they might have shared a common source of raw materials. The Mesa Verde black-on-white pottery was produced at three locations: Sand Canyon, Castle Rock, and Mesa Verde. Archeological evidence indicates that nearly every household had at least one member who worked as a potter. Trench kilns were constructed away from pueblos and closer to sources of firewood. Their sizes vary, but the larger ones were up to long and thought to have been shared kilns that served several families. Designs were added to ceramic vessels with a yucca-leaf brush and paints made from iron,
manganese,
beeplant, and tansy mustard. Most of the pottery found in 9th century pueblos was sized for individuals or small families, but as communal ceremonialism expanded during the 13th century, many larger, feast–sized vessels were produced. Corrugated decorations appear on Mesa Verde gray wares after 700, and by 1000 entire vessels were crafted in this way. The technique created a rough exterior surface that was easier to hold on to than regular gray wares, which were smooth. By the 11th century these corrugated vessels, which dissipated heat more efficiently than smoother ones, had largely replaced the older style, whose tendency to retain heat made them prone to boiling over. Corrugation likely developed as ancient potters attempted to mimic the visual properties of coiled basketry. Corrugated wares were made using clay from formations other than Menefee, which suggests that ancient potters selected different clays for different styles. Potters also selected clays and altered firing conditions to achieve specific colors. Under normal conditions, pots made of Mancos shale turned grey when fired, and those made of Morrison Formation clay turned white. Clays from southeastern Utah turned red when fired in a high-oxygen environment.
Rock art and murals Rock art is found throughout the Mesa Verde region, but its dispersion is uneven and periodic. Some locations have numerous examples; others have none, and some periods saw prolific creation, while others saw little. Styles also vary over time. Examples are relatively rare on Mesa Verde proper, but abundant in the middle San Juan River area, which might indicate the river's importance as a travel route and key source of water. Common
motifs in the rock art of the region include anthropomorphic figures in procession and during copulation or childbirth, handprints, animal and people tracks, wavy lines, spirals, concentric circles, animals, and hunting scenes. As the region's population plummeted during the late 13th century, the subject of Pueblonian rock art increasingly shifted to depictions of shields, warriors, and battle scenes. Modern Hopi have interpreted the
petroglyphs at Mesa Verde's Petroglyph Point as depictions of various clans of people. Starting during the late Pueblo II period (1020) and continuing through Pueblo III (1300), the Ancestral Puebloans of the Mesa Verde region created plaster
murals in their great houses, particularly in their kivas. The murals contained both painted and inscribed images depicting animals, people, and designs used in textiles and pottery dating back as far as Basketmaker III, . Others depict triangles and mounds thought to represent mountains and hills in the surrounding landscape. The murals were typically located on the face of the kiva bench and usually encircled the room. Geometric patterns that resemble symbols used in pottery and zigzag that represent stitches used in basket making are common motifs. The painted murals include the colors red, green, yellow, white, brown, and blue. The designs were still in use by the Hopi during the 15th and 16th centuries. ==Climate==