Franktown Cave
Encyclopedia
Franktown Cave, located 2.5 miles (4 km) southwest of the town of Franktown
in Douglas County, Colorado
, was a prehistoric rock shelter
between about 6,400 BC
and AD 1725. Excavations at the site unearthed a remarkable number of perishable items, including corn, plant material and clothing. Items found in the cave reflect cultural influences by people of the mountains, Arkansas River
basin in southern Colorado and Plains sites in northeastern Colorado.
The first men and women to inhabit the cave were hunter-gatherer
s. Over time they created material goods for their comfort, task-simplification and religious celebration. There is evidence of the site being a campsite or dwelling as recent as AD 1725.
198 feet (60.4 m) above Willow Creek, a tributary of Cherry Creek
that flows into the South Platte River
at Denver, Colorado
, 25 miles to the north. It is more than 6000 feet (1,828.8 m) in elevation
.
Situated on Palmer Divide
, which separates the South Platte River
basin from the Arkansas River
basin, Franktown Cave is its largest documented rock shelter in the area. Palmer Divide is a east-west ridge in central Colorado that runs perpendicular
to the Rocky Mountains
between Denver and Colorado Springs
and east to Limon, Colorado
. Monument Hill
, is the highest point of the divide at about 7500 feet (2,286 m).
The cave was created when water eroded the soft, water soluble
layers of Dawson Arkose
formation through seeps
below a thick, hard shelf of Castle Rock Conglomerate
. The area provides two key raw materials that were used for tool-making:
Near the rock shelter, spring-fed streams traverse a land of scrub oak, plains grassland
and open ponderosa pine forest.
The early, middle and late Archaic periods are all represented at the Franktown cave. The early period was marked by a nomadic hunter-gatherer
lifestyle in the mountains and foothills, adapted to smaller game and greater reliance on gathering wild plants for food than their Paleo-Indian ancestors. During this period new stone tools were created to process and prepare plants for meals. Gilmore submits that bison antiquus
, the primary source of food for the Paleo-Indian, became extinct
due to increasingly warm and arid climate changes of the Holocene Altithermal
period [a warm period about 9,000 to 5,000 years ago]. To survive people adapted by hunting smaller game and gathering plants, seeds, and nuts.
The Franktown cave is the only site as of 2005 to have evidence of middle Archaic occupation on the Palmer Divide. Based upon archaeological evidence, it appears that mountain people had longer transitional periods through the Archaic and Ceramic periods than those on the Plains. Franktown Cave residents who were adapted to the mountain culture, were also slow in integrating bow and arrow technology and other advancements.
At Franktown, Early Ceramic artifacts include a pottery fragments, a fragment of a coiled basket similar to the earlier periods, and a small corner-notched point - which seems to indicate that the uptake of new technology was slower here than at some other sites during the Early Ceramic period.
Artifacts from AD 780-1290, the middle Ceramic period, include small, distinctive side-notched projectile point
s, clothing, charcoal, potsherds, a sinew and twig net, and corn cobs. The sinew and twig net is similar to hoops used for several Native American nations' games. Franktown artifacts from the Archaic period reflect influence from the southern Apishapa culture
of the Arkansas basin and the Upper Republican plains people of the South Platte basin in northeastern Colorado and northwestern Kansas. The pottery has the conical shape of Plains Woodland pottery and the cord-markings and rims of Upper Republican pottery.
Population size and mobility changed during the Archaic periods. The number of early Ceramic period sites increased, reflecting an increase in population. By the middle Ceramic phase, there was a marked decrease in the number of sites. People stayed in one place for shorter periods of time, and were part of smaller and more mobile groups.
were Apache
Native Americans. While the Middle Ceramic period reflected a significant decrease in population, it appears as if there was an upswing in eastern Colorado population during the Protohistoric period.
. The table below shows the artifacts found by cultural period and period of time, dated by Accelerator Mass Spectrometry (AMS)
and Radiocarbon dating
.
Franktown Cave is similar to Trinchera Cave Archeological District
and Chamber Cave, all showed significant evidence of residence, including a wealth of perishable items. The Trinchera and Chamber Cave sites are located south of Franktown Cave in the Arkansas River
basin and were influenced by the people of the southern Great Plains
.
The site has also been subject to excavations before the 1940s by local Boy Scouts and has been subject to looting over time.
in 2006.
Franktown, Colorado
Franktown is a census-designated place in Douglas County, Colorado, in the United States. The population was 395 at the 2010 census. The Franktown Post Office has the ZIP Code 80116. Pike's Peak Grange No...
in Douglas County, Colorado
Douglas County, Colorado
Douglas County is the eighth most populous of the 64 counties of the state of Colorado, in the United States. The county is located midway between Colorado's two largest cities: Denver and Colorado Springs...
, was a prehistoric rock shelter
Rock shelter
A rock shelter is a shallow cave-like opening at the base of a bluff or cliff....
between about 6,400 BC
Anno Domini
and Before Christ are designations used to label or number years used with the Julian and Gregorian calendars....
and AD 1725. Excavations at the site unearthed a remarkable number of perishable items, including corn, plant material and clothing. Items found in the cave reflect cultural influences by people of the mountains, Arkansas River
Arkansas River
The Arkansas River is a major tributary of the Mississippi River. The Arkansas generally flows to the east and southeast as it traverses the U.S. states of Colorado, Kansas, Oklahoma, and Arkansas. The river's initial basin starts in the Western United States in Colorado, specifically the Arkansas...
basin in southern Colorado and Plains sites in northeastern Colorado.
The first men and women to inhabit the cave were hunter-gatherer
Hunter-gatherer
A hunter-gatherer or forage society is one in which most or all food is obtained from wild plants and animals, in contrast to agricultural societies which rely mainly on domesticated species. Hunting and gathering was the ancestral subsistence mode of Homo, and all modern humans were...
s. Over time they created material goods for their comfort, task-simplification and religious celebration. There is evidence of the site being a campsite or dwelling as recent as AD 1725.
Geography
Franktown Cave is a rock shelterRock shelter
A rock shelter is a shallow cave-like opening at the base of a bluff or cliff....
198 feet (60.4 m) above Willow Creek, a tributary of Cherry Creek
Cherry Creek (Colorado)
Cherry Creek is a tributary of the South Platte River, long, in Colorado in the United States.-Location:Cherry Creek rises in the high plateau, east of the Front Range, in northwestern El Paso County...
that flows into the South Platte River
South Platte River
The South Platte River is one of the two principal tributaries of the Platte River and itself a major river of the American Midwest and the American Southwest/Mountain West, located in the U.S. states of Colorado and Nebraska...
at Denver, Colorado
Denver, Colorado
The City and County of Denver is the capital and the most populous city of the U.S. state of Colorado. Denver is a consolidated city-county, located in the South Platte River Valley on the western edge of the High Plains just east of the Front Range of the Rocky Mountains...
, 25 miles to the north. It is more than 6000 feet (1,828.8 m) in elevation
Elevation
The elevation of a geographic location is its height above a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface ....
.
Situated on Palmer Divide
Palmer Divide
The Palmer Divide is a ridge in central Colorado that separates the Arkansas River basin from the Missouri River basin. It extends from the Front Range of the Rockies in central Colorado, eastward toward the town of Limon....
, which separates the South Platte River
South Platte River
The South Platte River is one of the two principal tributaries of the Platte River and itself a major river of the American Midwest and the American Southwest/Mountain West, located in the U.S. states of Colorado and Nebraska...
basin from the Arkansas River
Arkansas River
The Arkansas River is a major tributary of the Mississippi River. The Arkansas generally flows to the east and southeast as it traverses the U.S. states of Colorado, Kansas, Oklahoma, and Arkansas. The river's initial basin starts in the Western United States in Colorado, specifically the Arkansas...
basin, Franktown Cave is its largest documented rock shelter in the area. Palmer Divide is a east-west ridge in central Colorado that runs perpendicular
Perpendicular
In geometry, two lines or planes are considered perpendicular to each other if they form congruent adjacent angles . The term may be used as a noun or adjective...
to the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
between Denver and Colorado Springs
Colorado Springs, Colorado
Colorado Springs is a Home Rule Municipality that is the county seat and most populous city of El Paso County, Colorado, United States. Colorado Springs is located in South-Central Colorado, in the southern portion of the state. It is situated on Fountain Creek and is located south of the Colorado...
and east to Limon, Colorado
Limon, Colorado
Limon is a Statutory Town that is the most populous town in Lincoln County, Colorado, United States immediately east of Elbert County. The population was 2,071 at the 2000 census. Limon has been called the "Hub City" of Eastern Colorado because Interstate 70, U.S. Highways 24, 40, and 287, and...
. Monument Hill
Monument Hill (Colorado)
Monument Hill or Back Forest Divide Pass is a elevation mountain pass in the Palmer Divide in central Colorado in the United States. The pass dividing the Arkansas River drainage system to the south and the Platte River drainage system to the north is the high point on between Denver and Colorado...
, is the highest point of the divide at about 7500 feet (2,286 m).
The cave was created when water eroded the soft, water soluble
Solubility
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
layers of Dawson Arkose
Arkose
Arkose is a detrital sedimentary rock, specifically a type of sandstone containing at least 25% feldspar. Arkosic sand is sand that is similarly rich in feldspar, and thus the potential precursor of arkose....
formation through seeps
Seep (hydrology)
A Seep is a moist or wet place where water, usually groundwater, reaches the earth's surface from an underground aquifer.-Description:Seeps are usually not of sufficient volume to be flowing beyond their above-ground location. They are part of the limnology-geomorphology system...
below a thick, hard shelf of Castle Rock Conglomerate
Conglomerate (geology)
A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...
. The area provides two key raw materials that were used for tool-making:
- MicrocrystallineMicrocrystallineA microcrystalline material is a crystallized substance or rock that contains small crystals visible only through microscopic examination.-See also:* Macrocrystalline* Microcrystalline silicon* Protocrystalline* Rock microstructure...
rock in white chalcedonyChalcedonyChalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of the minerals quartz and moganite. These are both silica minerals, but they differ in that quartz has a trigonal crystal structure, while moganite is monoclinic...
, light yellow and caramel that was formed from petrified woodPetrified woodPetrified wood is the name given to a special type of fossilized remains of terrestrial vegetation. It is the result of a tree having turned completely into stone by the process of permineralization...
during the PaleocenePaleoceneThe Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...
period. Projectile pointProjectile pointIn archaeological terms, a projectile point is an object that was hafted to a projectile, such as a spear, dart, or arrow, or perhaps used as a knife....
s and small bifaceBifaceIn archaeology, a biface is a two-sided stone tool and is used as a multi purposes knife, manufactured through a process of lithic reduction, that displays flake scars on both sides. A profile view of the final product tends to exhibit a lenticular shape...
s were made from microcrystallineMicrocrystallineA microcrystalline material is a crystallized substance or rock that contains small crystals visible only through microscopic examination.-See also:* Macrocrystalline* Microcrystalline silicon* Protocrystalline* Rock microstructure...
rock. - Wall Mountain tuff rhyolite from the OligoceneOligoceneThe Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
age for flake tools.
Near the rock shelter, spring-fed streams traverse a land of scrub oak, plains grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
and open ponderosa pine forest.
History
Prehistoric cultural periods of eastern Colorado are traditionally identified as: Paleo-Indians at the earliest, Archaic, Ceramic and Protohistoric phases. Evidence of Franktown Cave habitation began with the early Archaic period about 6,400 BC and continued through each of the remaining cultural periods to AD 1725.Archaic periods
People of the Archaic period moved seasonally to gather wild plants and hunt game, such as deer, antelope and rabbits. Late in the Archaic period, about AD 200-500, corn was introduced into the diet and pottery was made for storing and caring food.The early, middle and late Archaic periods are all represented at the Franktown cave. The early period was marked by a nomadic hunter-gatherer
Hunter-gatherer
A hunter-gatherer or forage society is one in which most or all food is obtained from wild plants and animals, in contrast to agricultural societies which rely mainly on domesticated species. Hunting and gathering was the ancestral subsistence mode of Homo, and all modern humans were...
lifestyle in the mountains and foothills, adapted to smaller game and greater reliance on gathering wild plants for food than their Paleo-Indian ancestors. During this period new stone tools were created to process and prepare plants for meals. Gilmore submits that bison antiquus
Bison antiquus
Bison antiquus, sometimes called the ancient bison, was the most common large herbivore of the North American continent for over ten thousand years, and is a direct ancestor of the living American bison....
, the primary source of food for the Paleo-Indian, became extinct
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
due to increasingly warm and arid climate changes of the Holocene Altithermal
Holocene climatic optimum
The Holocene Climate Optimum was a warm period during roughly the interval 9,000 to 5,000 years B.P.. This event has also been known by many other names, including: Hypsithermal, Altithermal, Climatic Optimum, Holocene Optimum, Holocene Thermal Maximum, and Holocene Megathermal.This warm period...
period [a warm period about 9,000 to 5,000 years ago]. To survive people adapted by hunting smaller game and gathering plants, seeds, and nuts.
The Franktown cave is the only site as of 2005 to have evidence of middle Archaic occupation on the Palmer Divide. Based upon archaeological evidence, it appears that mountain people had longer transitional periods through the Archaic and Ceramic periods than those on the Plains. Franktown Cave residents who were adapted to the mountain culture, were also slow in integrating bow and arrow technology and other advancements.
Ceramic periods
The Early Ceramic, or Woodland, period began in the Plains about AD 0, distinguished by the introduction of the cordwrapped pottery and the bow and arrow. People also began to live in small settlements.At Franktown, Early Ceramic artifacts include a pottery fragments, a fragment of a coiled basket similar to the earlier periods, and a small corner-notched point - which seems to indicate that the uptake of new technology was slower here than at some other sites during the Early Ceramic period.
Artifacts from AD 780-1290, the middle Ceramic period, include small, distinctive side-notched projectile point
Projectile point
In archaeological terms, a projectile point is an object that was hafted to a projectile, such as a spear, dart, or arrow, or perhaps used as a knife....
s, clothing, charcoal, potsherds, a sinew and twig net, and corn cobs. The sinew and twig net is similar to hoops used for several Native American nations' games. Franktown artifacts from the Archaic period reflect influence from the southern Apishapa culture
Apishapa culture
The Apishapa culture, or Apishapa Phase, a prehistoric culture from A.D. 1000-1400, was named based upon an archaeological site in the Lower Apishapa canyon in Colorado. The Apishapa River, a tributary of the Arkansas River, formed the Apishapa canyon...
of the Arkansas basin and the Upper Republican plains people of the South Platte basin in northeastern Colorado and northwestern Kansas. The pottery has the conical shape of Plains Woodland pottery and the cord-markings and rims of Upper Republican pottery.
Population size and mobility changed during the Archaic periods. The number of early Ceramic period sites increased, reflecting an increase in population. By the middle Ceramic phase, there was a marked decrease in the number of sites. People stayed in one place for shorter periods of time, and were part of smaller and more mobile groups.
Protohistory
The groups of people during this period became much more diverse, were more likely to settle in a location or a couple of locations, cultivate food, domesticate animals, make pottery and baskets, and perform ceremonial rituals. Artifacts from 1540 to 1860, the latest prehistoric period, include corn cobs, arrow points and what appear to be Dismal River Gray ceramic fragments. It is believed that the people of the Dismal River cultureDismal River culture
The Dismal River culture refers to a set of cultural attributes first seen in the Dismal River area of Nebraska in the 1930s by archaeologists William Duncan Strong, Waldo Rudolph Wedel and A. T. Hill...
were Apache
Apache
Apache is the collective term for several culturally related groups of Native Americans in the United States originally from the Southwest United States. These indigenous peoples of North America speak a Southern Athabaskan language, which is related linguistically to the languages of Athabaskan...
Native Americans. While the Middle Ceramic period reflected a significant decrease in population, it appears as if there was an upswing in eastern Colorado population during the Protohistoric period.
Rock shelter description
The rock shelter, sheltered from extreme precipitation and temperature extremes, faced east. It is the largest documented Palmer Divide rock shelter as of 2005, measuring 40 feet (12.2 m) wide by 20 feet (6.1 m) at its deepest point. At the front edge of the cave, large rocks provided a protecting barrier. There is a lower level on the southern portion of the cave and another several yards higher on the northern side. The southern portion of the cave was dry which preserved most of the excavated items. The upper level had a water seep and few artifacts were found there.Artifacts by cultural period
Excavations were conducted intermittently since the 1940s focused primarily on the southern, lower level of the cave. 4000 pre-historic items were found at the site, 2180 of which were chipped stone artifactsArtifact (archaeology)
An artifact or artefact is "something made or given shape by man, such as a tool or a work of art, esp an object of archaeological interest"...
. The table below shows the artifacts found by cultural period and period of time, dated by Accelerator Mass Spectrometry (AMS)
Accelerator mass spectrometry
Accelerator mass spectrometry differs from other forms of mass spectrometry in that it accelerates ions to extraordinarily high kinetic energies before mass analysis. The special strength of AMS among the mass spectrometric methods is its power to separate a rare isotope from an abundant...
and Radiocarbon dating
Radiocarbon dating
Radiocarbon dating is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" ,...
.
| Cultural Period | Component Age / Contributing Dates | Baskets and ceramics | Clothing | Corn / plant | Stone | Other |
|---|---|---|---|---|---|---|
| Early Archaic 6400-3800 BC |
6400-3800 BC | Projectile points | ||||
| Middle Archaic 3800-1250 BC |
3350-2470 BC | Coiled basket | Sandal, rabbit hide robe |
|||
| Late Archaic AD 1250 - 150 |
AD 130-420 | Charcoal | ||||
| Early Ceramic AD 150-1150 |
AD 660-800 | Coiled basket, early ceramic sherd |
||||
| Middle Ceramic AD 1150-1540 |
AD 720-1290 | Middle ceramic sherd, plain bowl sherd |
Legging, moccasin | Corn cob | Charcoal, Sinew/twig net |
|
| Protohistoric Protohistory Protohistory refers to a period between prehistory and history, during which a culture or civilization has not yet developed writing, but other cultures have already noted its existence in their own writings... AD 1540-1860 |
AD 1280-1950 | Corn cob, corn kernel | Dismal River sherd | |||
Franktown Cave is similar to Trinchera Cave Archeological District
Trinchera Cave Archeological District
The Trinchera Cave Archeological District is an archaeological site in Las Animas County, Colorado with artifacts primarily dating from 1000 BC to 1749 AD, although there were some Archaic period artifacts found...
and Chamber Cave, all showed significant evidence of residence, including a wealth of perishable items. The Trinchera and Chamber Cave sites are located south of Franktown Cave in the Arkansas River
Arkansas River
The Arkansas River is a major tributary of the Mississippi River. The Arkansas generally flows to the east and southeast as it traverses the U.S. states of Colorado, Kansas, Oklahoma, and Arkansas. The river's initial basin starts in the Western United States in Colorado, specifically the Arkansas...
basin and were influenced by the people of the southern Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
.
Artifact counts and description by category
The counts of artifacts by category are:| Category | Count | Description of items |
|---|---|---|
| Chipped stone artifacts | 2180 | Stone artifacts, including 160 projectile points and projectile point fragments, similar to those found in the Mount Albion complex and Magic Mountain (MM3) sites. |
| Ground stone | 234 | |
| Potsherds | 862 | Cordmarked and plain potsherds |
| Perishable artifacts | 351 | Baskets, cordage, stitched hide, weaving tools, a moccasin and woven yucca sandals, rabbit fur robe, a sinew net, digging sticks, arrow and atlatl foreshafts, and other items made of bone and wood. |
| Ecofacts, meaning evidence of ancient environments |
791 | Bundles of grass, reeds, yucca fiber, cactus pads, and pine needles. Corn cobs and kernels, animal bone, shell and wood. Animal bones found were those of larger mammals like bison, deer and elk. There were also bones for cotton rat, pack rat, porcupine, prairie dog, rabbit turkey, and weasel. |
| Total | 4418 | Perhaps there were duplicates, such as animal bone, fiber, wood, etc. |
Excavation and studies
| Date | Name | Comments |
|---|---|---|
| 1942 | Hugh Capps, a graduate of the University of Denver | The first professional excavation. The collection of 208 excavated items were donated to the University of Denver Department of Anthropology |
| 1949 | Professor Arnold Withers, University of Denver Department of Anthropology | Excavation, creation a map of the rock shelter interior |
| 1952 | Professor Arnold Withers, University of Denver Department of Anthropology | Excavation of a total of 1779 items, creation a map of the rock shelter interior |
| 1956-57 | Gerold Thompson, graduate student; Arnold Withers | Excavation of 1292 items, integration with earlier University of Denver findings, creation of a plane table map of the site and began a report, but was unable to complete them due to his armed services commitment. |
| 1976 | Dr. Sarah Nelson, University of Denver Department of Anthropology | A one-day site investigation that included location and collection about 570 remaining items and creation of photographs and drawings of the site. |
| 2003 | National Science Foundation grant, presumably to the University of Denver | Analysis and dating of perishable items. |
The site has also been subject to excavations before the 1940s by local Boy Scouts and has been subject to looting over time.
Historical significance
Franktown Cave was added to the National Register of Historic PlacesNational Register of Historic Places
The National Register of Historic Places is the United States government's official list of districts, sites, buildings, structures, and objects deemed worthy of preservation...
in 2006.
See also
- Cedar Point VillageCedar Point VillageCedar Point Village is an archaeological site located in Elbert County, Colorado near Limon. It is a prehistoric residential site with artifacts of the Dismal River culture and likely inhabited by early Apachean people....
- archaeological site in southwestern Colorado also having Dismal River culture artifacts - List of prehistoric sites in Colorado