Field Trip 2 ANT 309 February 20, 2008 Directions
STOP 1: Sweet Springs Preserve, Los Osos
Take Foothill to Los Osos Valley Road (LOVR). Turn Right on LOV. Travel 5 miles (Approximately) into Los Osos. Continue through lights and through Los Osos. On west side of town turn Right on Pine Street. Turn right on to Ramona. Continue on Ramona (200 yards or so) until you encounter Sign marking Sweet Springs Preserve on your left. Park.
KEEP TRACK OF YOUR MILEAGE BETWEEN STOPS!
STOP 2: Boosinger Park in Pismo Beach
Return to Los Osos Valley Road. Turn left on to LOVR. Travel east to Highway 101. Get on freeway (101) going south. Take the South 1/ Pismo Beach exit in Pismo Beach. At Stop Sign after coming off freeway, turn left on to Price Street. Take Price one block to Stop Sign at Wadsworth (Longboard’s Grill). Turn left on to Wadsworth and follow it up the Hill for about ¼ mile to Boosinger Park on the left. Park. Convene on rocks overlooking Pismo Beach.
IF you get lost or have a problem. Call Social Sciences Department Secretary: 756-2752
Today's trip is intended to demonstrate some of the practicalities of subsistence and paleoenvironmental research. In class last week, I told you that archaeological sites produce evidence of human subsistence and in so doing provide some information on environmental conditions that were present in the area surrounding an archaeological site at the time it was occupied. In the course of pursuing subsistence activities, human beings sample the environments around them, albeit in ways that are somewhat biased (e.g., they were mostly interested in species that are edible). Still, the faunal remains recovered from archaeological sites can tell us a little bit about the nature and distribution of habitats that were present prehistorically.
On our first field trip we inspected a site adjacent to an exposed rocky coast—a type of coastline marked by rocky substrate and high energy in the intertidal zone due to surf action. The shellfish species that frequent that type of habitat include California mussels (Mytilus californianus), abalone (Haliotis spp.), turban snails (Tegula spp.), and limpets (Collisella spp.). Shells in the midden at San Geronimo Creek reflected the exposed rocky coast habitat present there now and in the past.
Excavations at a site on the San Luis Obispo exposed rocky coast produced the following:
Summary of Economically Significant Molluscan Remains from CA-SLO-267, a typical exposed rocky coast midden.
|
Taxon |
Common Name |
% |
|
|
|
|
|
|
|
|
Mytilus californianus |
California mussel |
84.9 |
Tegula funebralis |
Black turban snail |
8.9 |
Balanus spp. |
Barnacle |
1.2 |
Haliotis spp. |
Abalone |
0.5 |
Collisella spp. |
Limpets |
0.3 |
Pollicipes polymerus |
Leaf barnacle |
0.3 |
Others |
|
3.9 |
Total |
|
100.0
|
Today we will be looking at two different coastal environments and archaeological sites that reflect their exploitation:
Present-day Morro Bay estuary
Open Sandy Coast of Pismo Beach
We will also be looking at the Paleoestuary of Halcyon Bay
Morro Bay Estuary
Estuaries are environments that reflect convergence of freshwater and marine systems. They are products of sea level rise during what is called the Flandrian transgression when seas began to rise after about 18,000 years ago during the Last Glacial Maximum (LGM). At that time, sea level was perhaps 120 m lower than today and the shoreline of San Luis Obispo was in some places 10 km west of where it is today. What is now Morro Bay was nothing more than a freshwater creek , the main channel of which was well below the present-day water surface. As sea level rose, it gradually flooded this channel at the same time that the dunes which front Morro Bay today began to form. By at least 6,000 years ago the sea had nearly reached its present day level. And it had flooded a very wide area. At that time, sea level rise began to slow considerably, and sediments began to collect in the bay.
During the course of their development, estuaries provided different types of habitats for mollusks. The sediments that collected provided habitat for a variety of estuarine shellfish- clams and oysters that are adapted to the unique protected and partially saline/partially freshwater environments of estuaries. These mollusks were an important source of food for prehistoric people. The most common species at Morro Bay are:
Pacific Littleneck clam (Protothaca staminea)
Gaper clam (Tresus nuttalli)
Oysters (Ostrea lurida)
Washington clam (Saxidomus nuttalli)
Summary of Shellfish Remains from CA-SLO-215, a Typical estuarine midden at Morro Bay
|
Taxon |
Common Name |
Weight (g) |
% |
|
|
|
|
|
Protothaca staminea |
Pacific littleneck |
1574.4 |
67.2 |
Tresus nuttallii |
Gaper |
318.9 |
13.6 |
Ostrea lurida |
California oyster |
239.1 |
10.2 |
Saxidomus nuttalli |
Washington clam |
160.6 |
6.9 |
Macoma nasuta |
Bent-nosed clam |
21.6 |
0.9 |
Clinocardium nuttalli |
Cockle |
17.7 |
0.8 |
Mytilus californianus |
California mussel |
9.8 |
0.4 |
Total |
|
2341.8 |
100.0
|
Open Sandy Coast of Pismo Beach
The exposed coast of Pismo Beach represents a completely different marine habitat, and as a result presented a different set of shellfish species to prehistoric foragers. Most common were:
Pismo clam (Tivela stultorum)
Halcyon Bay: A Paleoestuary
Archaeological
site CA-SLO-832 is situated immediately to the south of Boolinger Park. Given its proximity to the open sandy coast of Pismo Beach and the rocky shore at Shell Beach, what would you expect for a shellfish assemblage in the midden?
DIRECTIONS
STOP 1: Sweet Springs Preserve, Los Osos
Take Foothill to Los Osos Valley Road (LOVR). Turn Right on LOV. Travel 5 miles (Approximately) into Los Osos. Continue through lights and through Los Osos. On west side of town turn Right on Pine Street. Turn right on to Ramona. Continue on Ramona ( 200 yards or so) until you encounter t Sign marking Sweet Springs Preserve on your left. Park.
KEEP TRACK OF YOUR MILEAGE BETWEEN STOPS!
STOP 2: Boosinger Park in Pismo Beach
Return to Los Osos Valley Road. Turn left on to LOVR. Travel east to Highway 101. Get on freeway (101) going south. Take the South 1/ Pismo Beach exit in Pismo Beach. At Stop Sign after coming off freeway, turn left on to Price Street. Take Price one block to Stop Sign at Wadsworth (Longboard’s Grill). Turn left on to Wadsworth and follow it up the Hill for about ¼ mile to Boosinger Park on the left. Park. Convene on rocks overlooking Pismo Beach.