Kid Questions & Answers 2

Archaeological Investigations
How do archaeologists know where to dig?
In the Bay Area, the most common sign of a prehistoric archaeological site - a place where people lived long ago - is dark soil with a greasy texture. This soil contains broken shells and animal bones. People often think that archaeological sites must be buried underground because they were occupied so long ago, but many very old sites can be seen right at the ground surface. Sometimes the archaeological soils are hidden under paving and buildings, as was the case at Emeryville.

In other circumstances, older archaeological soils have been buried under new layers of soil. This often happens when a site is located near a creek that has flooded during the past. Sometimes a site is accidentally buried, when new soil is brought to a construction site to fill up low areas or make the ground higher. In these cases, the archaeologist may not be able to tell that the site is there: it may only be found by chance when excavation starts at the site. Generally though, archaeologists can tell that an archaeological deposit is present by the appearance and texture of the soil on the surface.

Why did archaeologists want to dig at the Emeryville Shellmound?
As discussed above, the Emeryville Shellmound was known to be an important site that had been occupied for a long time. However, what made archaeologists want to excavate there was that they believed that investigations at the site could provide answers to important research questions.

Before beginning any archaeological excavation, the 1st thing an archaeologist does is prepare a research design. This is a set of questions that he or she thinks may be answered by the kinds of artifacts and other types of information that are likely to be present in the site. Often it is not possible to completely answer these questions, but we may at least find information that will contribute to new answers.

At Emeryville, because of earlier excavations, archaeologists already knew a lot about the kinds of materials they could expect to find at the site. This helped them to think about the questions that might be answered by the site. Their research design included questions they thought would be important to understanding Bay Area prehistory. Here are some of the questions archaeologists hoped to answer by studying the Emeryville Shellmound:
  • When was the site 1st occupied?
  • Can we recognize layers in the site? Can we identify changes over time in the kinds of tools people used and other ways that they lived?
  • What kinds of changes are evident?
  • How did the environment change over time?
  • Did the ways that the Emeryville people hunted affect the animal populations around them?
  • Did the ways that they hunted change over time?
  • Are there changes in where and how the dead were buried at the site?
These are only a few of the many questions archaeologists asked. There are many, many pieces to the "puzzle" and there is always more to find out.

How do archaeologists know about the age of the site?
Archaeologists can determine the relative dates of artifacts (older and younger) by the arrangement of layers in the archaeological site. The older layers are on the bottom of the site, and each layer above it - with most of the things it contains - is younger than the layers below.

Archaeologists also can learn about the absolute dates of artifacts and layers by using radiocarbon dating. This laboratory test can be used to date wood, bone or shell - anything that has been alive in the past. It works best on things that have been preserved by burning, so charcoal from fires often is used for dating.

This is how radiocarbon dating works: While they are alive, all living things absorb different types of carbon from the atmosphere. Some of this carbon, known as C14, is slightly radioactive. When a living thing dies, it stops absorbing carbon and the C14 it absorbed while it was alive starts to decay. Scientists know how long it takes for C14 to decay completely. By measuring how much C14 is left, compared with the amount of other carbon remaining in the samples, the age of the material can be measured.

Layers of soil (strata) in the archaeological depositIn this way archaeologists can find out when the wood burned in a campfire was cut down, or when the elk whose bones are found was killed for food. Archaeologists do not need to date everything in the site. Because we know that sites form in layers, we can assume that most items found close to each other are of the same age. Items found in the layers of the site below the dated material can be assumed to be older, while items found above the dated material can be assumed to be younger than the dated item.

How do archaeologists know how the people of Emeryville lived?
The arrangement of strata (soil layers) in the ground, and the things that are found in each layer, tells archaeologists how the ways that people lived changed over time. The bones and shells found in each layer tell a story about what people hunted and ate. The tools and other artifacts in the same layer show how they hunted and how they lived.

Archaeologist Max Uhle 1st excavated on the site in 1902Archaeologists have studied the Emeryville Shellmound several times. Archaeologist Max Uhle 1st excavated on the site in 1902. At that time, there was an amusement park on the site called Shellmound Park.

Uhle dug a large trench in 1 side of the mound and then tunneled to its base. He recovered many artifacts from the mound, and observed that it had distinctive strata. Based on his observations, Uhle concluded that over time the people who lived at the site had developed new and better tool types.

Another archaeologist, W.E. Schenck, observed and made many notes as the mound was leveled in 1924.

Leveling of mound in 1924He also excavated 3 large trenches in the base of the mound after that top part had been hauled away. Like Uhle, Schenck also observed layers in the mound, but he disagreed with Uhle about changes over time. He believed that the ways people lived stayed the same for many hundreds of years.

Findings from 1999 investigationsArchaeologists returned to the mound in 1999 to conduct more investigations.

By that time, only the base of the mound was left partially intact underground - about 8 feet (2.5 meters) of midden deposit, that mainly represented the earliest 1,000 years of occupation at the site. The part of the deposit that could tell about later times at the site had already been destroyed, back in 1924.

At the same time, archaeologists discovered another smaller mound nearby, which was occupied 400 to 600 years ago.

Some of the archaeological crew at workWhat did archaeologists do at the Emeryville Shellmound site in 1999?
Many people get involved in an archaeological excavation or "dig." A crew of 20 archaeologists, a backhoe operator, 3 Native American observers, and many specialist scientists participated in the 1999 project.

Archaeologists had many questions about:
  • Specialist scientists participated in the 1999 projectHow people lived at the Emeryville Shellmound and what they did there
  • What was important to their way of life
  • How their ways of life changed over time
  • What the environment of the Bay Area was like at the time the shellmound was occupied
To gather information to help find answers to these questions, the archaeologists dug very carefully by hand and passed all of the soil through fine-mesh screens so that artifacts and samples of shell and bone Trenchescould be collected. Ohlone (descendants of the people who lived at the site) observed the dig and recommended how human burials found in the site should be treated. Scientists and engineers also were needed, at the dig, to deal with hazardous materials left in the ground by the factories that had been located on the site.

In addition to hand excavation, archaeologists directed a backhoe, which dug trenches across the site.

These cuts across the site helped expose soil layers, which helped archaeologists washing dirt through screens to recover artifactsarchaeologists understand how the site had built up over time.

During the excavation of the Emeryville Shellmound in 1999, over 2,500 artifacts and samples were collected. In addition to artifacts (tools and ornaments), archaeologists also collected samples of the shells, animal bones, seeds, charcoal from fires, and soil from the site. Each artifact and sample was described, cataloged and labeled so archaeologists would know exactly where in the mound it came from, how it had been collected, and what it was.

What did archaeologists learn about Shellmound Park in 1999?
IShellmound Parkn addition to the prehistoric Native American deposit, the archaeological investigation also uncovered artifacts from Shellmound Park, an amusement park that had been built on the mound site in 1876. Most of what is known about Shellmound Park comes from historic documents.

Because we have historic maps and records, we do not need to rely on archaeology alone to find out about the park. We know that Shellmound Park included picnic grounds, shooting galleries on piers extending into the bay, a racetrack, several bars and dance pavilions, a photography booth, and a carousel. People took ferries and a train to get to the bottlessite, where large group picnics and shooting competitions were held.

All the park buildings were demolished in 1924. However, in 1999, archaeologists discovered a buried trash dump that contained many bottles and other artifacts thrown away at the park. There were many gun shells in the dump, from target rifles used in the shooting galleries. Many different kinds of bottles and glasses also were found. These showed that visitors to the park drank beer and other alcoholic beverages, soda water, ginger ale, and tea or coffee. Etched on some of the glass mugs were the words "Stolen from Shellmound Park." These liquor bottlesartifacts help us to imagine what it might have been like to spend a day at Shellmound Park.

How did archaeologists study the material they collected?
After the excavation, archaeologists and other scientists studied the finds for many months. Artifacts were drawn, photographed, measured, and carefully described by specialists who looked for evidence of how they had been manufactured and used. A historian studied the Shellmound Park bottles, to determine where and when they had been made.

Many special studies were made of the prehistoric aSoda Bottlesrtifacts and samples. For examples, 1 lab analyzed samples of soil, to determine what minerals it contained, and whether it had been brought to the mound by people, or transported by wind and water. Other labs looked at pieces of obsidian from the site to determine how long ago they had been worked, and where they had come from. Charcoal was sent out for radiocarbon dating, to learn about the age of the site.

Zooarchaeologists - specialists in identifying mammal, fish and bird bone - examined thousands of pieces of bone to determine what animals the people of Emeryville used for food and tools, the habitats where animals were hunted, and how they were butchered. Paleobotanists studied seeds and other plant parts from soils and campfires to provide information about the plants that were present prehistorically in the site area, or were used for food.

Most important, after all the analyses were complete, archaeologists and other scientists prepared reports to share their results with other scientists and with members of the public.

What kinds of Native American artifacts did the archaeologists find?
Over 1,800 artifacts were found in the Emeryville site in 1999. These included tools and ornaments of bone, ground or chipped stone, and shell. Although materials like wood, leather and plant fibers certainly were used at the site, these materials rot away in the ground, and seldom are found in archaeological sites. Usually, it is only the more durable materials that remain to be studied by archaeologists. Studies of the artifacts provided much information about how the native people lived and worked.

Bone tools were the most common artifacts found at the site. Archaeologists identified bone awls, needles, harpoon parts, whistles, beads and pendants.

Bone Tools: Bone Needle & Bone Whistle
Many bone artifacts are highly polished. They became smooth and shiny, either as part of their finishing, or through use. A few were decorated with fine incised geometric patterns. A bone tool specialist determined which animals the bone tools were made from and how the tools were made. Many bone tools from the Emeryville Shellmound were made from deer metapodials, one of the lower front leg bones. Also common were the wing bones of large birds.

A chipped stone tool specialist looked at the many projectile points (arrowheads) and other tools that were excavated from the site. Many of the chipped stone tools found at Emeryville were made of obsidian, a volcanic glass. Obsidian is not present naturally in the Bay Area. Much of the obsidian found at Emeryville came from Napa, over 40 miles away. People in Emeryville probably traded with other groups to get obsidian to make tools. Other stone tools were made from chert, a rock that probably could be collected from the Temescal Creek.

Early on, people at the site used large spear points to hunt. Much later, they used bows and arrows, which use much smaller stone points. The 2 examples of projectile points, shown below, were made by the earliest and latest inhabitants of the Emeryville Shellmound. Other cutting tools also were made of obsidian or chert.

Projectile Points: Chert Point & Obsidian Point
CharmstoneArchaeologists also found mortars, pestles, "charmstones" and stone pendants. These types of artifacts are classified as groundstone because they are made by grinding 1 stone against another. Some of the groundstone implements like the charmstones are very finely shaped, while others are not much more than stream cobbles that have been used for pounding. Mortars (stone bowls) and pestles (pounding or grinding stones) were used to grind grass seeds, acorns and buckeye nuts into flour, and probably to grind other foods as well.

mortarNo one really knows why charmstones were made or how they were used. Because charmstones often are finely shaped and well polished, and would have required a lot of work and time to make, many archaeologists believe they had some special purpose. It is possible that they had spiritual importance to the native peoples, since we sometimes find them buried with the dead.

Possibly a charmstone in a grave might have been a sign of the person's wealth and importance in the village. Some Native Americans and archaeologists believe that charmstones were used for hunting or fishing "magic," perhaps attached to nets to bring good luck to the hunt. They may have had practical purposes as well.

The Emeryville people collected and traded shells with other groups to use for making beads and pendants. These ornaments must have been valuable to the native people, as they were not easy to obtain or make. Most of the shell beads and ornaments excavated in 1999 were found in graves.

Olivella shell beads - Spire-looped beads in top 2 rowsBeads were made from the shells of the olive snail (olivella), a small white or tan snail found in the bay and ocean.

The whole shell could be made into a bead by cutting or grinding off 1 end. Smaller circular or oval beads also could be cut from the sides of shells, and then perforated (drilled or punched) so they could be strung as necklaces or attached to clothing or other items.

Abalone shells also were used to make pendants - ornaments that could be hung around the neck or attached to clothing.

Abalone Shell Pendants
At Emeryville, only finished ornaments were found: there were no whole or broken abalone shells in the midden, so it is unlikely that the Emeryville people collected abalone as food or that they were able to get whole abalone shells.

Archaeologists believe that the people of Emeryville traded with the people who lived on the ocean coast to get abalone ornaments. Abalone ornaments of many different shapes, some with incised lines and dots, were found at Emeryville. Most of these were found in human graves. This tells us that these ornaments were especially valuable to the people, since they apparently did not use them in their everyday lives, but mostly used them to honor their dead.

How did the Native American people of Emeryville bury their dead?
We have no way of knowing what kinds of ceremonies the Emeryville people conducted, but we do know that they treated the dead reverently. Usually, when we find a grave in an archaeological site, we find only the skeleton, sometimes with tools and ornaments that were placed in the grave with the individual.

At Emeryville, many people were buried with shell ornaments and beads. These probably were strung or sewn onto headdresses or clothing, and were placed on the neck, head and body. Often the body also was covered with a powder or paste of red ochre, a red mineral pigment. The dead person's body was placed in a flexed position, with his knees drawn up to his chest. A pit 2 or 3 feet deep was excavated for the grave. We think that a fire sometimes was built in the pit before the person was placed in it. Probably after the fire went out, he or she was placed in the grave, usually face down or on his side, and the grave was filled with soil from the midden.

There may have been areas of the site that were used as cemeteries during different periods, but burials were present in many areas around the site. Archaeologists in 1999 noted that earlier graves often were disturbed prehistorically by the excavation of later graves. This suggests that most graves were not permanently marked. However, in 1 case, a group of 1 adult and several infant graves seems to have been marked by a pile of whale bones.

Was the Emeryville Shellmound a cemetery?
There were many graves in the Emeryville Shellmound. Some archaeologists and Native Americans believe that the site was mainly a special place to bury the dead and hold mourning ceremonies. Others believe that the people buried at Emeryville are the people who lived there, over the long history of the site. It is possible that the way the site was used changed over time. No one can know for sure.

Do archaeologists get to keep what they find?
Archaeologists do not keep what they find. When the analysis is complete and the archaeologist has tried to answer his or her own research questions about the site, archaeologists take archaeological collection to be stored in a museum or other special facilities. This is a way of making sure that the collection and information will be available for other researchers to study in the future. For most archaeologists, what is important is "not what we find, but what we find out."

In respect for the wishes of Ohlone descendants, human remains and the artifacts found with them at Emeryville were not placed in a museum, but were reburied in the ground, in a place where they would be safe from disturbance in the future.

Where happens to the artifacts and samples after they have been studied?
After analysis was completed, the artifacts and samples were taken to the Phoebe Apperson Hearst Museum of Anthropology at the University of California, Berkeley for permanent curation. There they will be carefully stored and preserved so that they can be studied by other archaeologists. There is always more to learn. Replicas of some of the artifacts will be displayed at the Community Room at the Bay Street Center in Emeryville.

Human skeletons that would have been destroyed by the cleanup or redevelopment of the site were excavated respectfully by archaeologists. Some Ohlone descendants prefer that no archaeological analysis be conducted on human remains or associated artifacts. The Native American observers at Emeryville decided that they did not want scientists to study the skeletons found at Emeryville. However, archaeologists were permitted to make casts - exact copies - of many of the artifacts that were found in graves, so that these could be studied. Human remains and associated artifacts were then reburied in a place that would be safe from future disturbance.