8,000 YEARS OF CHANGE AT MORRO BAY:
AN ARCHAEOLOGICAL PERSPECTIVE
Native Americans have relied on the changing natural resources of the Morro Bay region for the past 8,000 years - hunting, gathering, and fishing from local camps and villages. Archaeological sites contain the physical remains of these past activities and environments, and archaeologists, Native Americans, and scientists from various disciplines work together to collect and interpret the information that lies in the ground. Although our predecessors left no written history, the oral traditions of their descendants, combined with physical evidence uncovered during archaeological excavations, can create a picture, as yet incomplete, of past lifeways.
Archaeologists begin an investigation with certain questions in mind, such as:
Objects and features found at a site - stone and bone tools, plant and animal remains, house pits and fire hearths - are examined to answer these and other questions about how human cultures have changed over time.
- - How old is the site?
- - How long did people live here?
- - How did they obtain and prepare their food?
- - How has the natural environment changed over the last 8,000 years?
Most archaeological studies conducted in California are the result of construction projects. Fortunately, State and Federal laws protect archaeological sites, so we are able to retrieve information that would otherwise be lost. It must be remembered, however, that archaeological excavations, by their very nature, are destructive, so studies must be conducted in a controlled and systematic manner, with careful documentation of each find.
ARCHAEOLOGISTS AND NATIVE AMERICANS WORK TOGETHER
Members of the local Native American community are present as representatives of their tribes and as descendants of the people who once occupied the site. One of their most important tasks is to give advice regarding the proper and dignified treatment of human burials and other sacred remains, according to traditional customs.
The map shows the position of the site on the landscape, and the location of artifacts, excavation units, and natural features like rock outcrops, trees, and streams. If a cultural resource is destroyed, the map may be the only detailed record of what it looked like.
ARCHAEOLOGISTS USE MANY DIFFERENT KINDS OF TOOLS AND EQUIPMENT
Backhoes are sometimes used in the first stage of excavation, to remove recent, disturbed soil, and to look for archaeological deposits that may not be visible on the surface. They can also be used at the end of a project, to make sure that no important features were missed.
Soil is excavated in a controlled manner; units usually measure 1 x 1 meters (about 3 x 3 feet), dug in 10 centimeter increments. Most commonly shovels are used; very hard soil may require picks. The excavator is careful to watch for changes in soil color, clusters of rock, and other things that might indicate a feature such as a fire hearth, house floor, or artifact cache.
When archaeologists notice anything unusual, like hard-packed soil or a cluster of artifacts, they trade their shovel for a trowel. Slow and careful excavation is necessary because certain features can provide important clues about prehistoric activities. For instance, a fire hearth may contain charcoal that can be used to date the site.
Excavated soil is passed through mesh screens to remove most of the dirt and to catch stone tools, bits of animal bone, and other cultural artifacts. These are carefully recorded and put into bags to be cleaned and studied in the lab. Sometimes a sample of soil is taken back to the lab and sorted for very tiny items - shell beads, bits of fish bone, burnt seeds - things that are too small to be caught in the field screens.
Once an excavation unit is finished, a soil scientist draws a careful profile of the various soil layers, noting their color and texture, and the location of features like shell clusters or house floors. By close examination of each layer, the soil scientist can determine how the soil was laid down (by wind, water, or erosion), and even the age of the deposited material.
SHELL, BEADS, BONES, AND STONE - MAKING SENSE OF WHAT WE FIND
Shell fragments are commonly found in coastal sites, usually scattered throughout an excavation unit, but sometimes found in distinct clusters. A sample of shell is taken to the lab for species identification. This information tells us which foods were available (or preferred) during any given period. Knowing the habitats where species spent their lives helps us understand which environments were important to Native Americans. For example, mussels are non-burrowing species that colonize the open rocky coast, while burrowing thin-shelled clams and Pacific Oysters thrive in estuarine settings. Changes in the relative abundance of rocky coast and estuary shellfish can help us reconstruct changes in the coastal landscape, as well as the origin and development of Morro Bay.
WHAT WE FIND|
|WHAT IT IS
a) mussels and abalone
b) clams and oysters
|WHAT IT MEANS
collection from outer coast rocks
collection from estuary habitats
Marine mammal and fish bone are common elements in Morro Bay archaeological sites. The excavation unit and depth where each bone is found are carefully recorded. The bone fragments are examined by specialists and identified as to body part and species. Several bones identified to a single species could either represent a number of individuals or a single animal, so the "minimum number of individuals" is estimated, based on the number of like body parts. The presence of certain species offers evidence of how the environment changed over time. Species size, behavior, and habitat can indicate the type of tools and techniques required for their capture.
WHAT WE FIND|
|WHAT IT IS
a) sea otter, harbor seal
b) Northern fur seal
c) pacific herring
e) yellowtail tuna
|WHAT IT MEANS
year-round, near shore/estuary hunting
winter hunting of migratory animals
estuary fish easily caught with nets while spawning
hook and line fishing off the rocks
live in warm ocean waters, probable
evidence of El Nino event
Historic observations indicate that local Native Americans used shell money as a medium of exchange for food and other items. Archaeological data (such as the identification of bead manufacturing sites) indicate that shell money wasn't used until after A.D. 1000. This information allows archaeologists to understand how economic systems developed and changed over time.
WHAT WE FIND|
|WHAT IT IS
a) Olivella disc beads
b) mortar and pestle
c) obsidian flakes
d) Cottonwood Point
|WHAT IT MEANS
used as currency in money economy
acorn processing and possible storage
long distance trade (include map of sources)
this particular bow and arrow style
point was used after A.D. 1400
In most areas, the mortar and pestle, commonly associated with acorn processing, are found later in time than the handstone and flat millingslab used for crushing hard seeds. Bowl mortars are the best tools for processing oily acorns, pounding them into a mush with a long, narrow pestle. Storage of acorns allowed the people to remain in their village year round rather than searching far and wide for food each season.
Obsidian artifacts found in the coastal region came from only a few parts of California, including Napa Valley and the Mammoth Lakes Coso Volcanic Field. The original location of obsidian found in coastal sites can be determined using a method called X-ray fluorescence. The obsidian's distinctive chemical elements are identified, and matched to a known group of "finger-print" elements that identifies each source.
The style of projectile points changed through time, with large atlatl darts used by the earliest cultures, and small arrow tips used with the bow and arrow much later in time. The size and shape of projectile points can tell us when they occurred in time relative to each other. To give a specific time period to each point form, they must be found alongside shell or charcoal that can be dated using radiocarbon analysis.
CULTURAL AND ENVIRONMENTAL CHANGE IN THE MORRO BAY AREA
PRIOR TO 10,000 YEARS AGO
Between 10,000 and 20,000 years ago, sea level was up to four miles off the modern coastline. If humans had inhabited this area, evidence of their presence would be under water.
Eight thousand years ago, sea level was about 5 to 10 feet lower than it is today. Over the next several thousand years, a warming trend melted glaciers and ice caps, raising the level of the sea. Estero Bay was characterized primarily by a rocky outer coast, with only a few sandy beaches. At Morro Bay, ocean water began to fill the low-lying river valleys, mixing fresh and salt water in an estuarine environment.
An 8000 year old site at Cayucos containing only mussel and abalone shows us that early inhabitants focused on collecting shellfish from the rocky intertidal zone. People living closer to the newly formed bay began to take advantage of estuarine resources. Fish were commonly caught with hook and line. Various seeds, including grasses, tarweed, and red maids, also contributed to the diet and were ground on flat millingslabs with hand-held manos.
- Mussel and abalone shell fragments, milling-slabs, manos, and bone gorge fishhooks provide the first evidence of early lifeways in the Morro Bay area.
There are few archaeological sites from this period. Populations were low, with small family groups moving frequently from one area to the next. They camped near productive mussel and abalone beds, collecting and processing these foods, then moved on to the next resource-rich area.
- Early populations moved frequently, covering coastal and interior regions.
Morro Bay reached its maximum size about 5000 years ago, when sea level stabilized. A recently excavated archaeological site, SLO-165, dating between 5500 and 4500 years ago, is located on the northern shore of this expanded bay.
The large bay provided an excellent, relatively stable environment for diverse birds, fish, shellfish, and mammals. The sand spit enclosing the bay was created by winds and water from north to south � a site on its northern end dates to 4000 years ago.
Site SLO-165 contained over 15,000 estuary fish bone fragments including requiem sharks, Pacific herring, and sculpin. Herrings spawn at night in very shallow water and are easily caught with nets. Sculpins inhabit the lower depths, within 60 feet of the surface, and were likely caught with hook and line.
- New, more efficient bone fishhooks, found in pairs held together with cords, were used to capture estuarine fish such as sculpins.
Thousands of shell fragments scattered throughout site SLO-165 are identified as common estuary species: clams, oysters, and moon snails. Clams are usually found deep in estuary mud and were probably collected using wooden digging sticks (which are not preserved in sites). Oysters are easily obtained from rocks.
- Estuary clams were obtained by digging in the mud. Oysters could usually be taken directly off estuary rocks.
Bird bone found at the site included ducks and geese, brown pelican, loons, and cormorants. Estuary waterfowl were likely caught with nets, weighed down with small stones with grooves or a circle of tar around their circumference. These stone items were found at the site.
- Nets made of marsh grasses, held down with net weights, were used to capture both fish and fowl.
Deer was the most common land mammal represented by bone fragments found at the site. Sea mammal bone included sea otter, northern fur seal, harbor seal, and California sea lion.
- Large points, notched for attachment to spears and atlatls, were used to hunt both land and sea mammals.
A large amount of burned acorn hull fragments found at the site indicates a reliance on acorns much earlier than is noted in other parts of California. These nuts required extensive processing, including shelling, pounding in a mortar, and leaching. Acorn mush was commonly cooked in baskets with the use of heated rocks.
- Acorns were an important food source. Rich in nutrients, they can be stored for future use.
- Large Olivella rectangle beads and Olivella spireground beads were used as personal adornment.
- The rich estuarine environment provided abundant resources for such things as food, clothing, and basketry, allowing Native people to settle in one place for much of the year.
1500 - 1000 YEARS AGO
A large Morro Bay site, now lying under the P.G.&E. Power plant, was excavated during the 1960s and dates between 1500 and 1000 years ago. A large house floor was evidenced by hard-packed earth in a roughly circular formation with post holes around its circumference. Several central fire hearths were also noted. The floor measured about 30 feet in diameter and could have held up to 50 people. Charred tule fragments were found overlying the floor, representing what was left of the structure's framework.
- The largest house floor ever found on the California Coast was exposed at a site near Morro Rock.
A dramatic increase in the number and variety of shell and steatite beads occurs during this period. Over 40 distinct bead styles have been identified by archaeologists. A diversity of shell tubes and bone pins were also made.
- All parts of the Olivella shell were used to make beads. As fashions changed, so did bead styles.
Identical radiocarbon dates from the exposed stumps indicate an extremely dry period about 1000 to 700 years ago. The drought had a profound affect on the environment of California, disrupting the way of life developed by Native Americans dependent on bay and coastal resources.
- Submerged tree stumps found in Sierran lakes give evidence of an earlier drought throughout California. Photo by Emory Kristof, National Geographic Society.
The Morro Bay estuary is constantly changing. Silting occurs at the river mouths, creating extensive tidal marshlands and mudflats, reducing the total area of the bay. Remnant marshes give evidence of its former extent.
Just as modern towns encircle the estuary, Native American villages clustered around this rich environment. At the time of European contact, a complex culture was in place involving trade, money, food storage, and bead manufacturing.
Objects such as tule balsa boats, clothing, wooden implements, and baskets do not survive long in the soils of Morro Bay, however, information has been preserved in the written accounts of early explorers and in the oral traditions of Native elders.
- Native people went out to greet Spanish explorers in tule balsa boats. We do not know when these boats were first used, as tule decays quickly.
A description of Native inhabitants of the region is found in the dairy of an early Spanish explorer:
Native Americans continue to live in the Morro Bay region. Many still adhere to the values and beliefs of their ancestors. There is, for example, a desire to continue the art of basket making which is an important part of their heritage. There is also a renewed interest in Native language and music. A language program, founded in 1993 by the Advocates for Indigenous California Language Survival, apprentice young adults to fluent elders, encouraging them to speak informally, bringing the language of their heritage into their daily lives.
- "Their houses, shaped like half globes, are neatly built; each one is capable of sheltering four or five families...The houses have one door on the east and one on the west, with a skylight on the roof... ...as a protection from the sun, they cover their heads with little woven trays or baskets, decorated with handsome patterns... The fishhooks are made of pieces of shell fashioned with great skill and art. For catching sardines, they use large baskets, into which they throw the bait which these fish like... a distance of two leagues from the mission there are as many as eight springs of bitumen or thick black resin...it is used chiefly ...for caulking their small water craft and to pitch the vases and pitchers which the women make for holding water.
Pedro Fages, Spanish military commander 1772
The California Indian Basketweavers Association
'Working to preserve and perpetuate California Indian Basketry'
16894 China Flats Road
Nevada City, CA 95959
The Advocates for Indigenous California Language Survival
'To foster the restoration and revival of indigenous California languages'
Native California Network
1670 Bloomfield Road
Sebastapol, CA 94572
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