Choshi Geopark

A geopark is
where we canlearn everything
and have fun.★

“The earth,”“living creatures,”and the “humanactivity” areinterconnected

Human activity

History, culture, and industry

Living creatures
Plants and animals

The earth

Choshi Geoprk related "Exhibitions"
Choshi city youth and cultural hall
“Choshi Geopark Exhibition room”

We will guide you
through the entire park!

【Entrance fee】 free
【Hours】9:00 to 17:00【Closures】every Monday(except if Monday is a holiday, it will be closed
Tuesday.) National holidays(except for May 5th and November 3rd)
1046 Maejuku-cho, Choshi City, Chiba Pref., Japan
〒288-0031 Phone:81-(0)479-24-8911※All the fun of Choshi geopark in one place.

Horizon Observatory【Entrance fee】Adult ¥ 380, Elementary andJunior-high school children ¥ 200, Over 65 ¥ 330【Hours】April to September, 9:00 to 18:30
October to March, 9:00 to 17:00
The last entry is 30 minutes before closing【Closures】None1421-1 Tennoudai, Choshi City, Chiba Pref., Japan
〒288-0024 Phone:81-(0)479-25-0930※Various fossils and ambers from Choshi can be viewed.

Tokawa Mini Furusato Museum【Entrance fee】free【Hours】10:30 to 15:30【Closures】Tuesdays and Wednesdays (except for holidays)
Inquiries for Tokawa Mini Furusato Museum“Choshi Tourism Association” office
Phone:81-(0)479-22-1544

Cho-Pi(Choshi’s publicist)

I was born in a cabbage field in Choshi.
If you want to know anything about
Choshi, leave it to me, “Cho-pi.”

Geo-Cho(Choshi Geopark PR ambassador)

My job is to showcase Choshi and the
Choshi Geopark. My hat is modeled
after geological strata and Cape
Inubousaki lighthouse. My blue bangs
represent waves of the Pacific Ocean.

※Here, you can find about the history of Tokawa town.
You can also view the collection of shellfish fossil researcher, Mr. Tomio Watanabe.

Editor:The Choshi Geopark Promotion Council office
Phone:81-(0)479-24-8911 FAX:81-(0)479-21-6622
URL http://www.choshi-geopark.jp/

Illustration: Chiba Prefectural Choshi High School(Hinano Jitsukawa and Risa Ishige)

Scan this QR codeto access the Choshi
Geopark website.

Choshi Port Tower ·Medogahana

Kurohai

At Kurohae Fishing Port
can see “conglomerate,”
formed from small rocks, andblackish colored “andesite”,
formed through solidificationof magma approximately 20
million years ago. (P7)

It is a 57.7m tower. At the foot of
the tower, you can see a stratum
called “Medogahana,” which was
deposited around the time the
Sea of Japan formed. (P7)

Yoyamashell moundSoy-sauce Factories

Yoyama shell mound

Higeta Shoyu Co. Ltd.
factory

Sennintsuka
Bronzite andesite Conservation Park ●The “Choshi Geopark
Exhibition room”is the basefacility of Choshi geopark, andprecious fossils of Choshi are
exhibited here. (cover)

Soy sauce production has beenflourishing in Choshi since the Edo
Periods. (P17)(Inquiry for a factories tour)
Choshi factory of Yamasa Corporation
Visit desk at 81-(0)479-22-9809
Higeta Shoyu Co. Ltd. Choshi,
Choshi office at 81-(0)479-22-0080

Here are traces of humanactivities from approximately
3500 years ago. (P13.14.15)

Choshi fishing port
Wholesale Market 3

Choshi city youth andcultural hall

Choshi fishing port
Wholesale Market 2

Choshi
Port Tower

Medogahana

Choshi fishing port
Wholesale Market 1
Moto-choshi
stationNakanocho station

Choshi stationYamasa soy-sause
factory
Horizon Observatory
・Mt. Atagoyama

This hill is rock formed in the
period that dinosaurs lived.
From the observatory, you can
see the entire Choshi Peninsula.
(P6. Cover)

KurohaiKasagami-kurohae
stationKannonstationNishi-ashikajima
stationChoshi city youth
and cultural hall

Ashikajima
stationCape Inubousaki ·Lighthouse

Here, You can see the lighthouseand sedimentary rocks, which
deposited in the shallow sea
during the age of dinosaurs. You
can also see many coastal
plants in this region. (P7.11)

Byoubugaura Cliff
AEON mall
Choshi

It is a 10-km-long cliff eroded
by waves. This cliff is made ofstrata deposited in the ocean
approximately 3 million years
ago. (P8)

Inuiwa Rock ·Sengaiwa Rock

3This symbol shows you points ofinterests within the Choshi Geopark.

These rocks were formed in
the period that dinosaurs lived.
Inuiwa rock looks like a dog.
(P6)

Kimigahama
stationByoubugaura Cliff
InuboustationHorizon Observatory
Mt. Atagoyama

Cape Inubousaki

Climax forest of Laurel
forest at Tokai Shrine ●Inuiwa RockSengaiwa Rock

Tokawa townscape●

Tokawa Houman Rocks
station2

Interesting.

A lot of cabbages are
harvested in Choshi too.
These are all gifts fromthe earth.

RK

A
GEOP

What is a Geopark?

“Geo” means theplanet Earth andthe ground, andof course weknow what“Park” means.

I get it!!

During the Edo period, people
were able to use the waterway of
the Tone River, and that is why
the soy sauce industry
flourished. The climate is also
perfect for growing cabbage.

So everything isbecause of theearth of Choshi.

The logo for the Japanese
Geoparks Network

Is a geopark a park just forgeology and topography?
What, really?
Tell me more!

The earth of
ChoshiThat‛s right. For
example, soy sauce
has been made in
Choshi since theEdo periods, right?

People have been living in Choshi
since ancient times thanks to“the gifts from the earth.”

Geopark activities are that everyone know about Choshi through blessingsfrom the earth. Through the geopark, We hope you‛ll fall in love with
Choshi.
5

Of course topography
and geology areimportant, but that‛s
not all.

One of the important roles of geoparks is topreserve precious heritage of geology andtopography, and to pass it onto the future.

At the geopark, byunderstanding “the gifts
from the earth,” you canreally feel the charm of
the earth.

Fish is also a giftfrom the earth,right?

What is a“geopark” forwhich Choshi was
first certified in
Chiba pref.?

The gifts fromthe earth?

They are sites
where you canunderstand “thegifts from theearth.”

Right,
it‛s famous!
4

1. When Choshi had been located further south ❷★Events that occurred 130 million years ago The eastern shore
Cape Inubousaki has a
precious geologicalfeature; hence, it isdesignated as anatural monument(nationally designated).

Choshi cityof Choshi consists ofrocks made of sand andmud which had accumulated
in the ocean during 130 to
110 million
years ago.

designated［Nationally
natural monument ］

earth of Cho
nts ofshiev
EPaleozoic
The properties of the groundbeneath you are called “geology.”
By studying “geology,” you canunderstand the history of theearth.

150 million(?) years ago

1. When Choshi had been located further south ❶Ancient
continent
Direction ofplate movement

CHOSHI
Shallow sea

How the earth of Choshi was formed?

Mesozoic
Cenozoic
130 million years ago
20 million years ago
3 million years ago

Here

Cape Inubousaki

I’S
CHOSH TORYGEOHIS★Events that occurred 150 million(?) years ago

After these rocks
formed, the earth of
Choshi moved several
thousand kilometers
toward the north.

When dinosaurs were alive, the part of the earth that became
Choshi was formed further south than the current location.

Plates?

The oldest rock(called“Atagoyama Group”) was formed
when overlying materials were
pushed against the continent andstripped-off as the oceanic platesubducted under the continental
plate. (Bottom figure)

Deep sea

Choshi 130 million years ago (Modified from Asahiko Taira, 1990)

2. When the Sea of Japan and the Japanese archipelago formed★Events that had occurred during 25 to 15 million years ago

The Sea of Japan hadn’t always been there.
Approximately 15 to 14 million years ago

Approximately 25 million years ago

CHOSHI？

CHOSHI？

Formation of the Sea of Japan

Ocean
Plates are sheets ofrocks approximately
100 km thick thatcover the Earth‛ssurface. Plates moveseveral cm per one
year.

Continent
When a plate is subducted,
the top layer of the sediments is
stripped-off toward the continent.

Edge of the continentContinent
The position of Japanese archipelago back then
Modified from Nuclear Waste Management Organization of Japan (2004)

Houman Rocks
Islet off the coast ofNagasaki
The rocks that formed
approximately 20 million
years ago when lava
cooled7

During approximately 25
to 15 million years ago, theedge of the continent slowly
had separated, created theJapanese archipelago and
the Sea of Japan.

Oceanic plate

MantleSubducting undera continent

Ocean
Hence, the rocks like
Inuiwa Rock,Sengaiwa Rock, and
Mt.Atagoyama areformed during thattime.

Medogahana

A cliff under the Choshi
Port Tower
The rocks that formed
from mud accumulated in
the ocean approximately
17 million years ago.

Inuiwa RockMt. Atagoyama
6The gifts from the earth
Using the rocks and minerals of Choshi

3. When the Kanto region was an ocean★Events that occurredsince approximately 3 million years ago◆Kurohae tile

There are many tile shops in the Kurohae district of Choshi. In
the past, they were known as “Korohae fired tiles” and were awell-known local specialty of Choshi.
These tiles were made from high-quality clay as a raw material
mined from the Kurohae district. These clays were once themudstone portion of a geological body that became attached toJapan approximately 150 million(?) years ago (see p6).
At present, these clays have all been mined.

Choshi city

When I lookcarefully, I can see
beautiful stripes.

Here
Kurohae tile
This cliff is called
Byoubugaura Cliff. It hadformed since approximately 3
million years ago, when the almost
Kanto region was an ocean.

◆Choshi stone

The old stone walls of Choshi often have rocks with roughsurfaces. These rocks are called “Choshi Stone,” the sandstone
formed 120 million years ago(see p7). In addition to building
materials, “Choshi stone” was used as a rough whetstone.

Whetstone◆Iron manufacturing with iron sandBlack bands are occasionally seen on the sandy beaches of
Choshi. If you place a magnet near this black band, black grains
are attracted to the magnet. These grains are iron sands. At theshore of Choshi, these iron sands were mined as a source ofiron until a few decades ago.

What was once in theocean is now visible on
the land. The movementof the earth is amazing,isn‛t it?

When the resin (tar) of trees was buried undergroundover many years, it hardens and becomes amber.
Choshi is one of the three major producers of amber inJapan. The oldest amber in Japan having been
discovered here.

◆Shark tooth

Sand and mud
accumulate inwater.

Let’s look at from a distance Byoubugaura Cliff !
Many fossils fromthe strata of various
eras have beenfound in Choshi.

Many shark tooth fossils have been found in Choshi. Even a fossil of tooth of a Megalodon,
a giant shark of over 10 m, has been found.
9

Many layers of
sediments
accumlate in theocean, and theselayers form
stripes. These
stripes are called“geological strata.”

When the environment changes,
the sizes and contents of thesediment changes.

◆Ammonite◆AmberRepetition
forms the stripe
patterns.

Iron sand of the sandy beachThe gifts from the earth
Fossils of Choshi
Ammonite lived during the age of dinosaurs and was related tooctopus and squids.The fossilized part is the hard outer shell.
In Choshi, a large fossil with a diameter of over 50 cm has beenfound.

Isn‛t the cliff along
the south coast of
the Choshi Peninsula
so beautiful?

←West

Around this area,
only the ground of
Choshi has been
lifted up a lot.

East→

The strata of
Byoubugaura Cliff
inclines to thewest, doesn‛t it?

Cross section of the groundOkutama
1000

Strata of the new era-1000

Uplifted ground

-2000
-3000
-4000

ChoshiTokyo

0Strata of the old era

Inclined strata to the west
A cross section of the Kanto region showsthat the strata of the same era as the
Byoubugaura Cliff are present several
thousand meters under the ground of Tokyo.

m

Cross section of the earth(Modified from Hiroyoshi Suzuki (1988))
8

[Let’s go look at some coastal plants]
There are strong, salty
winds along the coast.
Many coastal plants thathave adapted to such anenvironment are growing
there.

URE

CREAT

Flora and fauna of Choshi

Really?

The Choshi geopark issurrounded by theocean in three
directions; hence, theanimals and plants
here have special
characteristics.

Thunbeng Lily (summer)
Bright red and orange flowers
bloom during summer.

In the Choshi coast, we can see the coastal plants with flowers for each season.
(Blooming period)
Roundleaf chastetree(summer-fall)

Beach pearlwort(spring-summer)

Japanese wild radish(spring)[Let’s go find some sea creatures]
Rocky shores
during the low
tide are full ofcreatures.

This is a sea bat.
You can often findthem in the rocky
shores if you go
during the spring.

Wow, there arelots of gulls in
Choshi.

Solidiago Virgaurea subsp. leiocarpa(fall)
It is believed that theseflowers came fromwarmer regions in thesouth with the Kuroshio
Current, and became
widespread.

11

False bindweed(summer)

Angelica japonia(spring-summer)
Ajania pacifica (fall)
Related to chrysanthemums.
Flowers bloom from October
to November.
There are many plants at
Choshi, the northernmost
location, possible for theirsurvival, such as “Ajania
pacifica.”

In winter, gulls suchas the black-tailed
gull and herring gull,as well as
cormorants andducks are often seenaround fishing ports.

Black-tailed gull

Choshi has also
migratory tiny
birds, wow.

Tringa brevipes

From spring tosummer, streaked
shearwaters are seen
hunting sardines
over the sea, andmigratory birds,
such as sandpipers,
can be seen at theshores.
10

N
HUMA TYI
ACTIV

People living in Choshi in the Ancient times[Forest in Choshi· Laurel forest][ What is a shell mound? ]LaurelA “shell mound” is where ancientpeople threw their garbage.
Yoyama shell mound in Yoyama
town, Choshi city, shows thatpeople lived here
since the Jomon period,
approximately 3500 years ago.

Wow.

Laurel leaves
There are numerous
valleys in Choshi.

It stays green throughout theyear, and it has characteristic
shiny leaves. It is often foundin warm areas with lots ofrain during summer.

Nanatsuike Pond

Yoyama shell mound
These are Jomon tools
found at the Yoyamashell mound!
These are the gifts fromthe Nature.

Jomon items foundat the Yoyama shell moundIn Choshi, Laurel forests are often
found in areas with steep slopes andin the forests of old shrines.

—Garbage is treasure!—Let‛s go look forit next time.

Challenge!!
What nature‛s gift wasused? And for what?
Let‛s try the quiz on
the next page.
13

I am sosurprised!
There are somany tools!

Japanese Laurel
forests were mostly
destroyed becauseof development.

This is what it
looks like when
you look up.

All the leaves grow in search of sunlight;
hence, the leaves don’t overlap.
That is why it looks like the sky is hidden.
As you can see, Choshi is blessed with rich flora andfauna from the land to the sea.
12[ The location of the Yoyama shell mound ]During the Jomon
period, thetemperatures werehigher than today
and the sea level was
higher. Hence, theocean spread toinland.

Ko-Kinuwan

Yoyamashell mound(Paleo-Kinu Bay)

Oku-Tokyowan

Challenge yourself to"Jomon period tools" quiz!

Q: What is it made from? What was it used for?
I hope you get it right!
Why was the
Yoyama shellmound so rich innature‛s gifts?

Jomon tools
fishhook

Materials
clay

?
? ?
The ocean area
during the Jomon
periodshell moundbenkei-gai

potsherd(dog cockle)

catch fishbones of dee

stone
implementstoneshell bracelets

I see !

The Yoyama shellmound during the Jomon
period looked like tothe left pictures.
People were able tocatch a lot of fishes
and animals.

boil food,cook,
and store
make tools
and hunt
animals

A: Answers•clay……potsherd……boil food, cook, and store •benkei-gai……shell bracelets……accessory•deer bones……fishhook……catch fish •stones……stone implements……make tools and hunt animals

The ocean and forests
are close. That is why
the bounty of the sea
and forests weregathered close-by.

How it is used

accessory(Paleo-Tokyo Bay)The “Yoyama shell mound” isan important place where we
can understand the lifestyle ofpeople duing the Jomon period.
Currently, the “Yoyama shellmound beautification association”
is working on its conservation.

Connect
things thatare relatedusing a line.

Hence, tools madein Choshi and thematerials were
popular evenoutside of Choshi.

shell bracelets

arrowheads

Jomon tools made in Yoyama and the materials to
make these tools were transported to inland areas.
15

14

N
HUMA TYI
ACTIV[ Soy sauce of Choshi ]That‛s right. Even today, companies
such as Ogura Shoyu, Takara
Shoyu, Higeta Shoyu, and Yamasa
Corporation are making soy sauce.
Higeta Shoyu and Yamasa
Corporation were establishedduring the 17th century, and havea long history.

Industries that make full use of
Choshi's regional characteristics

Choshi has been
famous for its
soy sauce
manufacturing.

We will show you how
the gifts from theearth have beenutilized in Choshi.

[ Eastward Re-location of Tone River]Tone River after the eastward relocation.

Tone River 1000 years ago.

Watarase River

Yamasa Corporation
Established in 1645

Kinu River

Higeta Shoyu
Established in 1616

Edo River

The reasons why manufacturing soy sauce flourished in Choshi①Producers of the raw materials were nearby
Soybeans and wheat were produced in Hitachi(Ibaraki) and Shimofusa (Chiba), and salt was
produced in Gyotoku (Chiba).
②The Eastward Relocation of Tone River
Raw materials were transported by ship and the
manufactured soy sauce was shipped to Edo.
The Eastward Relocation of Tone River made theshipping conveniently to Edo.

Tone River

Kasumigaura

Soybeans★

Tokyo Bay

Tokyo Bay

Provided by the Ministry of Land, Infrastructure, Transport and Tourism,Tone-river Upstream Office

Tone River

Wheat

Edo

Tone River

ChoshiThe old Tone River flowed into the Tokyo Bay. During the early stages of the Edo Period, becauseof the repair work conducted by Edo Shogunate, the river started to flow into the Pacific Ocean at
Choshi. This large-scale construction is known as “the Eastward Relocation of Tone River”. It issaid that this project was carried out to upgrade the water transport network, to protect Edo fromwater disasters, and to develop new rice fields. (“Edo” is now called Tokyo.)After "the Eastward Relocation", Tone Riverdeveloped as a waterway that connects Edo andnortheastern Pacific Ocean. Choshi, located at themouth of Tone River, flourished as a relay point
where loads were transferred from ships on the sea
to those on
the river.

Salt

Manufacturing ofsoy sauce in Choshi
is an industry thatmakes good use of
the advantages thatthe land offers.

A takase-bune carrying barrels(Chiba Natural History Museum and Institute, Otone Branch storage)
17

A takase-bune loaded with barrels(Owner: Ms. Yumiko Akimoto, photo provided by Nagareyama City Museum)How is Choshi related to the
Eastward Relocation of Tone
River ?

Takase-bune

The takase-bune has aflat bottom and astructure that has little
water draft (the depth of
the boat in water) sothat it doesn’t run
aground in a river withmany shallow areas.
16[ Agriculture of Choshi ][ Fishery of Choshi ]The rankings of the landing weights
at major fishing ports (2013)Land of Choshi(According to Jiji Press)

The plateau (slightly higher
ground) of Choshi is covered by“Kanto loam”, which is volcanic
ash that has turned into clay.
On this plateau, since it issuitable for growing crops,
many vegetables are grown.

Ranking

Fish landing
weights in Choshi
are really big! How
come so many fish
are caught here?

Vegetables with the top three yields
in Choshi (2012)

Many types of vegetables are
harvested in Choshi.
Choshi cabbage is especially
famous for its “Lighthouse markcabbage” brand.

(Ministry of Agriculture, Forestry and Fisheries)

Cabbage 81,100t
Daikon radish 55,100t (second in Japan)
Tomatoes 2,851t(third in Japan)

I see.

warm water vortex

Kuroshio Current
The average of the past 30 years

NAGASAKI

5

MATSUURA

6

KUSHIRO

7

NEMURO

8

HACHINOHE

9

MAKURAZAKI

10ISHINOMAKI

Choshi Tsuri-kinme

10
5
1

2

3

4

5

6

7

8

9

10 11

12 (Month)Comparison of monthly-mean temperatures of
Saitama and Choshi cities (Japan Meteorological Agency)
19

4(Japan Meteorological Agency)

Choshi City

15

0

SAKAIMINATO

Water temperatures at a depth of 100m during early July, 2002

Saitama City20

3

214,499
152,158
136,066
121,514
119,176
110,668
107,342
97,601
97,07386,087The Kuroshio
Current front

temperature

25

YAIZU

Offshore at Choshi is where "theOyashio Current" from north and"the Kuroshio Current" from south
meet. Because of this, a large
amount of plankton are here, andsmall fish like sardines gather here,mackerel and bonito
also gather here to
eat these fishes.

mixing zone

30

CHOSHI2(℃)

The Oyashio
Current front

cold water vortex

(℃)

1

water
temperature

Oyashio Current

The most suitable temperature
for cabbage cultivation is from
15 °C to 20 °C. Choshi is warm
even during winter, and that‛s
why cabbage grows well here
from fall to spring.

Fishing port Landing weight(t)Alfonsin, also called “Choshi Tsuri-kinme,”
is caught by a fishing method called“soko-Tatenawa”. It is designatedas a Chiba-brand marine product.
18