GEL 103 Lab/Field Project

1. POINT ST GEORGE, CA
TOLOWA DEE-NI’ HERITAGE AREA
All pictures taken by me, unless otherwise cited.

2. TOLOWA DEE NI’ HERITAGE SITE
Point St George is an archaeologic heritage site
(designated as such in 2002) in northern California, just a
few miles south of the Oregon border. It is the 3rd most
western spot in the United States. It is also only 12 miles
from my house, so I get the perk of being able to visit
often. (Bosworth)
Just looking at the panoramic views from the point,
coastal bluffs and geological ridges show the rich history
of area.

3.  Just a quick walk from the parking
area down through a valley, you
reach the edge of the beach
where you can find tidepools
aplenty during low tide. To the
north is a wide expanse of sandy
beaches and to the south is rocky
ridges full of geological treasures.

4. SEA THRIFT
(Armeria Martima)
Along the path leading up to the
beach there are many different
types of flowers and plants, but I
like the sea thrift the best.
Also called Lady’s Cushion, it is a
coastal perennial that looks like
grassy foliage when not in
bloom. It fares well even with
little water, and stands tall when
hit with salty water. (Jordan
Valley Water, 2017)

5. HERMIT CRAB
 Hermit crabs have over 800 species worldwide. Most are
ocean-dwellers, with only one being freshwater.
 They are omnivorous scavengers, with wide variety in
their diets, including bits of mussels and clams and
macroalgae. (Sartore, 2020)
 They aren’t *real* crabs, as they do not have an
exoskeleton and use found objects (usually shells) as
makeshift homes.
 Fossil records of hermit crabs using gastropod shells
date back to the Late Cretacious, and even older fossils
show them using ammonite’s shells as homes. ( Hermit
Crab, 2018)
(Paguroidea)

6. SOLITARY
ANENOME
 Scientific name is Anthopleura Sola
(Leslie, 2014)
 They are slow-moving carnivores,
using their tentacles to capture prey
and fend off other predators.
 Its tentacles are covered with
nematocysts, tiny stinging capsules
that inject poisons into their prey. If
you touch them your fingers many
feel a little tingly or numb.
(Klinkenburg, 2020)

7. PRINCIPLE OF
INCLUSIONS
This wall of rock was very interesting to
come across. The longer I looked at it,
the more I discovered.
I believe it is a good example of the
Principle of Inclusions, as the rocks that
are inclusions must be older than the
material that is surrounding them.
The weather and ocean eroding the
surface of this rock face gives us a good
look at many layers of geologic history.
(Tvelia)

8. Just yards from each other, there are
many examples of unconformities
along the coastline of Point St
George.
Layers of erosion on the top left
picture show us an example of an
angular unconformity.
The top right picture shows a
disconformity, exposed by erosion by
the ocean tides and coastal weather.
(Grippo, 2010)

9. ROCKS AND
TIDEPOOLS
There is no shortage of rocks,
shells, sea animals and other
treasures to explore along just
this little part of the coast.
We had it mostly to ourselves,
save for a few agate-hunters
scouring the shores for agates
washed up in the last tide.

10. COASTAL
AGATES
A popular pastime for northern
Californians (and southern Oregonians for
that matter) is hunting for agates along
beaches. I myself have hunted for them for
years and have quite a collection in jars
around my house.
An agate is a “translucent variety of
microcrystalline quartz”, usually formed in
cavities of igneous rocks, allowing silica to
form opaque spots or bands around the
translucent quartz. (King, 2019)
They come in a wide variety of colors, but
the most common that I have found would
be just clear with white bands or spots.

11. When I found this rock I wasn’t sure what it was. In fact, I am still on the fence! But after some
research I am fairly sure that it is an igneous rock called scoria.
It is similar in composition to basalt rock or pumice. It is formed when magma that is full of gas
flows or is blown from a volcano. The molten rock solidified before the gas has time to escape,
forming bubbles or tube-shaped holes within the rock. (King, 2020)

12. BASALT
This particular rock I believe is basalt,
which is the most common type of
rock on earth.
It caught my eye because of the
pitted erosion pattern on it. This
erosion could have been from water
drops, ocean etching, or gas bubbles
as it was forming from magma.
(Swanson, 2014)

13. REFERENCES:
 Bosworth, A. (n.d.). Point St. George Heritage Area. Retrieved June 11, 2020, from https://www.outdoorproject.com/united-
states/california/point-st-george-heritage-area
 Grippo. (2010). Unconformities. Retrieved June 11, 2020, from http://homepage.smc.edu/grippo_alessandro/unc.html
 Hermit crab. (2018, June 09). Retrieved June 11, 2020, from https://en.wikipedia.org/wiki/Hermit_crab
 Jordan Valley Water. (2017). Thrift. Retrieved June 11, 2020, from https://conservationgardenpark.org/plants/67/sea-thrift
 King, H. M. (2020). Scoria: Igneous Rocks. Retrieved June 11, 2020, from https://geology.com/rocks/scoria.shtml
 King. (2019). Agate gemstones. Retrieved June 11, 2020, from https://geology.com/gemstones/agate/
 Klinkenburg (Ed.). (2020). Introduction to Sea Anemones. Retrieved June 11, 2020, from
https://ibis.geog.ubc.ca/biodiversity/efauna/IntroductiontoSeaAnemones.html

14.  Leslie, J. (2014, May 28). Home. Retrieved June 11, 2020, from http://californiatidepools.com/anemones/
 Point St. GEORGE BEACH, Crescent City, CA. (n.d.). Retrieved June 11, 2020, from
https://www.californiabeaches.com/beach/point-st-george-beach/
 Sartore. (2020, April 14). Hermit crabs. Retrieved June 11, 2020, from
https://www.nationalgeographic.com/animals/invertebrates/h/hermit-crabs/
 Swanson, D. (2014). Volcano hazards program glossary - basalt. Retrieved June 11, 2020, from
https://volcanoes.usgs.gov/vsc/glossary/basalt.html
 Tvelia. (n.d.). Principles of Relative. Retrieved June 11, 2020, from http://www.thisoldearth.net/Geology_Online-
1_Subchapters.cfm?Chapter=4&Row=2
 University of Vermont. (2008, October 02). Relative Dating; Steno's Laws. Retrieved June 11, 2020, from
https://www.uvm.edu/perkins/evolution/qanda/?Page=time%2Frelative.html&SM=time%2Ftimemenu.html