History of Lamb Spring

It all started…

…in the outskirts of Littleton, Colorado where the Lamb Spring site was discovered by Mr. Charles Lamb in 1960 while digging a stock pond at the site of a natural spring.  He found several large bones that were identified by geologists with the U.S. Geological Survey (USGS) as the remains of mammoth, horse, camel and bison.  Dr. Waldo Wedel (Smithsonian Institution archeologist) and Dr. Glenn Scott (USGS geologist) then excavated the site in 1961 and 1962.  They found the bones of at least five mammoths, one of which was radiocarbon dated as slightly older than 13,000 years, suggesting that the animals visited the spring at the end of the last Ice Age.

Mammoths are part of a large group of animals called proboscidians that share a characteristic commonly called a trunk.  Other animals in this group include mastodons, stegodons, and elephants.  In contrast to elephants, mammoths lived only in the northern hemisphere.  The Columbian Mammoth was similar in size and appearance to African and Asian Elephants.  In contrast to elephants, mammoths lived only in the northern hemisphere.  The skull of a mammoth, such as the one represented by the cast you can see during a tour, is not a solid piece of bone but rather has several distinct areas within it, each performing a specific function.

After mammoths and other Ice Age animals had become extinct, people hunted and killed bison at the spring sometime between 8,500 and 9,000 years ago.  These people used stone tools associated with what archaeologists call the Cody complex.  In 1980 and 1981, Dr. Dennis Stanford (Smithsonian Institution archaeologist) also excavated the site and recognized evidence suggesting that people may have hunted the Ice Age mammoths.  He also found evidence of the remains of over 30 mammoths that died near the spring.

In 1995, The Archaeological Conservancy, with help from the Denver Museum of Nature and Science, the Smithsonian Institution, and Douglas County, purchased the 35 acres containing Lamb Spring.  Under the supervision of Drs. E. James Dixon and Paul Murphy, in 2002, students and volunteers from the Museum Studies Program at the University of Colorado-Boulder and the Denver Museum of Nature and Science (DMNS) participated in the excavation of the mammoth skull found previously by Dr. Dennis Stanford.  The excavated skull was transported to DMNS where scientists created a cast and mold.  The original specimen is still housed at DMNS.  The mammoth was likely a juvenile male or female that died about 13,000 years ago.  It may have been killed by humans or other predators, or it may have died of other causes.  Further excavations at the Lamb Spring Preserve will help to answer these and other questions about the prehistory of the site and the ancient environment of the region.


Lamb Spring is a unique resource for the Denver metropolitan region and is valuable for public education and research, because it is rich with information about natural and human history.  The Lamb Spring Archaeological Preserve (LSAP) is an internationally significant archaeological site containing bone beds of extinct Ice Age animals and artifacts from later human occupation at the spring.  Extinct Ice Age animals found at the site include over 30 Columbian Mammoths, the largest number known from any site in Colorado.  It also contains the remains of Ice Age camels, horses, sloths, llamas, and wolves.  The bones of these and other animals are preserved at the site.  In addition to animal remains, the site contains spear points and bison bones that are the remains of a hunt that took place at the spring sometime between 9,000 and 8,400 years ago. The artifacts left by humans indicate people hunted and camped around the spring for the past 9,000 years and possibly much longer.  LSAP presents an extraordinary case study because it holds the potential to alter theories about how and when humans first colonized the Americas near the end of the last Ice Age.  The site contains what may be some of the best-preserved evidence of the earliest humans to live in the North American Continent.

The Lamb Spring Archaeological Preserve (LSAP) offers many opportunities to provide the public a unique experience that combines education, scientific research, and tourism.

Site Background and History of Excavations

Mr. Charles Lamb, a Littleton, Colorado rancher on the South Platte River, excavated his spring in the summer of 1960 in order to develop a stock pond.  A mammoth tusk and several bone fragments were visible on the banks of the spring just below the water’s edge.  As Mr. Lamb completed the stock pond, he observed several bone fragments in one of his dragline buckets.  The bones were subsequently identified as Pleistocene mammal bones by Dr. G. Edward Lewis of the U.S. Geological Survey in Denver.  Dr. Lewis visited the site and identified the remains of mammoth, horse, camel, bison, antilocaprid (pronghorn-Pliocene or Miocene), and several smaller mammals, mostly rodents (Wedel 1962).  During the summer of 1960, Glenn Scott, a geologist for the U.S. Geological Survey joined Dr. Lewis and they attempted to determine the extent of the bone fragments around the spring.  While doing hand auger tests, they uncovered several worked flint chips which suggested late Pleistocene human activity (Wedel, 1962).

There appeared to be a relationship between the artifacts and the faunal assemblages because they were both in the same type of sediment and recovered from relatively the same depth (Stanford, Wedel, and Scott 1981).  Dr. C.L. Gazin, Curator of Vertebrate Paleontology, and Dr. Waldo R. Wedel, Curator of Archaeology form the Smithsonian Institution arrived to conduct excavations during 1961 and 1962.  Major funding was provided by the National Science Foundation through a two year grant (NSF G17609).  Dr. Gazin, Dr. Lewis, and C. Bertrand Schultz of the University of Nebraska State Museum, analyzed the vertebrate remains.  Glenn Scott and Holmes Semken of the University of Michigan served as the project geologists, and Dr. Wedel and his field assistant, George Metcalf, carried out the actual excavations.

The excavation during 1961-62 under Scott and Wedel resulted in the identification of eight geological levels, or stratigraphic units, that have been interpreted to represent different events during the geological history of the site. Bones and artifacts were uncovered in these various geological units with the most abundant occurring in the lowest stratigraphic level, Unit 1, which is approximately 5-6 feet below the surface.  Scott and Wedel hypothesized that Pleistocene peoples were responsible for the discharge and modification of the faunal (animal) remains found in Unit 1.  The evidence supporting their hypothesis proved inconclusive and the project was terminated by the end of the summer of 1962 (Stanford, Wedel, and Scott 1981).  A second bone bed was documented in Unit 2 and contained the skeletal remains of bison, eight Cody complex projectile points, a Cody complex knife, a scraper, a flake cutting implement, and several lithic (stone) flakes (Stanford and Fisher 1992).  Two radiocarbon dates on bone collagen from Unit 2 are 6,870 +/-350 B.C.

Excavations were resumed at the site in 1980-81 by Dr. Dennis Stanford and Glenn Scott of the Smithsonian Institution.  Dr. Russell Graham of the Illinois State Museum was the project’s paleontologist, and Mr. Jim Rancier served as excavation coordinator.   An early radiocarbon date of 11,140 +/- 1,000 B.C. run on bone by Wedel suggested to Stanford that the Pleistocene accepted archaeological evidence for humans in the Americas.  Dr. Stanford terminated the excavation and backfilled the site following the 1981 field season (Stanford, Wedel, and Scott 1981, Stanford and Fisher, 1992).

The excavations, under the direction of Stanford during 1981-82, exposed an area of some 2,400 square feet immediately north of the spring vent.  The primary focus of the excavations were the controversial Unit 1 bone bed.  However, he also recovered bison bones and artifacts from Unit 2 further documenting the extensive Cody complex occupation at the site (Stanford and Fisher 1992; Stanford, Wedel, and Scott 1981).  The evidence to support the fact that Lamb Spring is a Cody complex site is apparent from the character of the bison bone bed and stone artifacts that were recovered from the Smithsonian excavations.  The 1981-82 collections excavated by the Smithsonian Institution are housed the National Museum of Natural History in Washington, D.C.  The Cody complex component was the subject of a taphonomic and archaeological analysis that resulted in a master thesis at the University of Calgary, (Alberta, Canada) in 1984 (McCartney 1984).

In partnership with the Smithsonian Institution, the Denver Museum of Nature and Science (DMNS), the University of Colorado-Boulder, Douglas County, and the Archaeological Conservancy, in July 2002, Dr. E. James Dixon, and Dr. Murphy supervised the excavation of a Columbian Mammoth skull.  The mammoth skull was originally exposed, photographed, and reburied by the Smithsonian Institution in 1981, and was in need of professional conservation and preservation.

The excavation, removal, and transport of the skull took place in July 2002.  Under the supervision of Drs. Dixon and Murphy, students and volunteers from the Museum Studies Program at the University of Colorado-Boulder and the Denver Museum of Nature and Science (DMNS) participated in the excavation of the skull.  Once the skull was transported to DMNS it was exhibited, stabilized, and cast.  The complete Colombian Mammoth skull was on display in the North Atrium of the DMNS from July 2002 until January 2003.  Currently, it is in storage at the DMNS until there is an adequate storage facility at Lamb Spring.