Mikasa City Museum
Map of the exhibition

2nd Floor(usually Closed)

Celebrities
Exh.

1st Floor
Special Exh.
(usually Closed)

Coalmining
Exh.

PrisonExh.

Fossil Exh.
WicketCoal Exh.

ENTRANCE

Ver. 2.0
Edited in 2018 / Revised in October 2021

Shaded areas are private

Fossil Exhibition

❻❼❽ ❾
❶
❺
❷
❹ ❸

ENTRANCE
This room has more than 600 ammonites
fossils and about 400 other ones. Thisis one of the largest fossil collectionsin Japan. Especially, you can touch theselarge ammonites! Almost all fossils were
found from Hokkaido including to Mikasa,
and large parts of those were donations ofamateur collectors.
We also have the largest ammonite in Japan. Its diameter is about 1.3 m andweight is 560 kg.
Ammonites are extinct marine animals and closely related octopus, squid and cuttlefish. We
can obtain hard shells of those as fossils, however, there is no remain of soft bodies until now.
Those fossils are found from all over the world…North and South America, Europa, Africa,
India, Antarctica and, of coarse, Japan.
❶ Structures of ammonite conchs

AMMONITE

Air chambers

NAUTILUS

filled with gas
to maintain living depth

A shell of ammonites is divided into two parts, aphragmocone and a body chamber.
An inside of a phragmocone is sectioned by many septa.
Each divided chamber contains gas when an animal is alive,
and its buoyancy maintains depth of a body in a watercolumn. A narrow tube, “siphuncle”, runs through every
chamber.
A body chamber is located at the end of a conch andoccupied by a soft body.

Space in this ammonite shellis filled with sediment (grey)or minerals (yellow; calcite)

Nautilus has a shell with same structure. Therefore mode

Body chamber

containing soft tissues(organs and muscles)of life and locomotion of ammonites might be similar to
Nautilus.
1❷ Evolution of ammonites
Although we express in one-word“ammonites”, this group appeared in the
Devonian (400 million years ago) and wereextinct at the Cretaceous-Paleocene boundary(66 million years ago), and is composed bymore than 10 thousands species with large
variety. Therefore this group corresponds torelatively higher rank in scientific classification,
the Suborder Ammonoidea (this rank is sameas a group of recent birds).
This wall shows the evolutional tree of the Suborder Ammonoidea in about 330 million years.
❸ Classification of ammonites
The Class Ammonitida is the latest andthe only group of the Ammonoidea after theJurassic. All ammonites found from Hokkaido
are belonging to this group. It is obvious feature
Ammonitida has very complexly fluted suture(attachment between an outer shell and aseptum).
Ammonitida is divided into 4
subclasses...most ancient Phylloceratina,
l o o s e l y c o i l e d Ly t o c e r a t i n a , v a r i e dformed Ammonitina and heteromorphic
Ancyloceratina. In Hokkaido, about 500
species of those are found until now.
Small boxes shows families in each superfamily. Named families are exhibited in this museum. This
cladgram of ammonites are on the basis of Wright et al. (1996) and Rought et al. (2004)❹ Heteromorph ammonite
While a shell of popular ammonite is spiral on a plane, many
species have a variable ones, for example, a straight, a g-shape, atrombone-shape, and more geometrically complex ones. These nonplanispiral ammonites are called “heteromorph ammonites” ingenerally. Heteromorph ammonites are derived variable phylogenies,
but Ancyloceratina is a most famous group of heteromorph ammonites.
Hokkaido is known as a locality of abundant Ancyloceratina ammonites.
Nipponites is a genus of Ancyloceratina. However its shell looks liketangled at first sight, in fact, it forms a geometrically regular shell. As its
name derived from “Nippon (Japan)” shows, this ammonite is a symbolof fossils found from Japan.
2Reptiles in the Mesozoic
In the Mesozoic when ammonites lived, reptiles showed a very high diversity. Many
dinosaurs were on land, pterosaurs in the sky, and mosasaurs and plesiosaurs in the ocean in
the Mesozoic…but all of those (exception of birds diverged from dinosaur) were extinct at
the end of the Cretaceous with ammonites.
❺ Dinosaur
Dinosaurs are belonging to a group of reptiles, but are very closely relate tobirds (in correctly, modern birds are one group of dinosaurs).
Allosaurus fragilis, a carnivore dinosaur is displayed in this room. A skeleton
is a replica based on the specimen found from America, but a real left femur(thighbone) you can touch is placed too --- This bone shows one of common
features of dinosaurs. Dinosaurs stand with hind limbs vertical whiles otherreptiles with limbs sprawl out to either side.
❻ Pterosaurs
Pterosaurs are extinct flying reptiles lived in the Mesozoic. They have no
relationship with dinosaur and recent birds. They had wings formed by amembrane an elongated fourth finger supporting. This reconstruction modelis the most famous pterosaur, Pteranodon. A very close one was occurredfrom Mikasa and it is thought a largest pterosaur found from Asia (estimatedwing span is 6.8 m). But, larger pterosaurs are found from some parts of theworld. The hugest one with a ca. 12 m wing span is also the largest flying
animals in the history of this planet.
❼ Mosasaur
Mosasaurs are very close to monitor lizards, but lived in the sea. Their four
limbs became fins and its tail was looks like crescent to adapt swimming. Very
sharp teeth show this animal was carnivore. For example, ammonites fossils
with its bite marks, or digested mosasaur bones in another mosasaur’s stomach
are found.
This skeleton is a Platecarpus tympaniticus found from Kansus, USA.
Aboud 60 % of the skeleton, especiall 95 % of the skull is composed by realbone fossils.
❽ Taniwhasaurus mikasaensis“Yezo-Mikasa-Ryu (means dragon of Mikasa in Hokkaido)” is a kind ofmosasaurs. It was found in 1976 and designated as a natural monument of Japanin the next year. In 2007, this was given a scientific name as Taniwhasaurus
mikasaensis. It is also obvious that “Yezo-Mikasa-Ryu” is of Taniwhasaurus an only
speces found from the Northern hemisphere. This discovery is very important toestimate evolutional processes of mosasaurs.

Preserved position of this fossil (left)
and reconstruction skeleton of
Taniwhasaurus mikasaensis (right)
3

Recent studies revealed veritable appearance of mosasaur. So, in 2018, we started exhibiting a reconstruction model ofTaniwhasaurus mikasaensis (Yezo-Mikasa-Ryu) on the basis of the newest knowledge. Remarkable points are followed;
1) Ridge on a vertex: However it isn't clear in the skull of Yezo-Mikasa-Ryu, a ridge on the top of the head is acharacter of Taniwhasaurus.
2) Shark-like tail fin: In 2010, A well-preserved mosasaur fossil showed a crescent-like fluke similar to a shark.
3) Forked tongue: In 2005, scientists figured mosasaur had a forked tongue similar to snakes and monitor lizards on thebasis of paired opening on a skull4) Pattern of scales: Some skins of mosasaurs are found as fossils and the texture of scales of this model is based
those.
5) Lip covering teeth: While many previous reconstructions bared its teeth, this model has lips covering teeth because
recent sea snakes or aquatic lizards have those.
6) Color pattern: Aquatic animals tend tohave a darker back and a lighter belly. It
is a camouflague to merge into alighter sea surface when animals
are looked up and into a darker deep
when they are looked down. Coloring of thismodel is basically followed this role and, in
addition, a stripe pattern is based on recent
sea snakes.

Members of an ancient ocean
Not only ammonites, very abundant fossils are found from the Cretaceous in Hokkaido...forexample, bivalves, gastropods (snail), echinoids (sea urchin), crinoids (sea lily), fish bones, andshark teeth.
❾ Inoceramids
Inoceramids are extinct marine bivalves looks like mussels or oysters. Many
species compose of this group repeated appearance and extinction one by one andtherefore inoceramids are good index fossils. These were appeared in the Jurassic
and flourished throughout the Cretaceous, but disappeared before the end of theCretaceous.
This group contains the largest bivalve specimen in the history of the Earth (178cm in long and found from Greenland).
Column: Importance of the Cretaceous in Hokkaido
In the Cretaceous, the entire islands of Japanese Archipelago were under the sea. A
western half of Hokkaido was located in the eastern edge of the Asia Continent and was
gradually deepened sea floor faced to the Panthalassa (the paleo-Pacific). A unit of strata
deposited on this floor is called "Yezo Group" and distribute from the central Hokkaido and Sakhalin. Thickness of the Yezo
Group reaches about 8,000 m corresponds to about 50 million years of deposit time range.
Ammonites’ fossils found from there has much paleontological importance. First, those remain original 3D structures.
Therefore we can see fine spines, larval conch, or complex coiling.
Second, long-time deposited sediment recorded the rise and fall of each species of ammonites. Ammonite fauna foundfrom Hokkaido devided into three major groups, hence, the Boreal, the Tethys, and the Pacific-rim. Repetition of influx anddisappear of each fauna created the diversity of ammonites in Hokkaido.
4

Celebrities of Mikasa
From Mikasa, much talent went out into variable fields. In this museum,
relics related to two medical giants, an actress, and an athlete are
exhibited.

❶

❷

❸❹

ENTRANCE❶ Dr. KUROKAWA Toshio
黒川利雄 (1897– 1988)
Dr. Kurokawa was a clinician and a well-known diagnostician of stomach
cancers.
He graduated Tohoku Imperial University in 1922. He was a pioneer of cancer
screening with X-ray and endoscopes in Japan. Especially it is an accomplishment
he starts mass radiography for stomach cancers. He was awarded the First Class
Order of the Sacred Treasure ( 勲一等瑞宝章，right) in 1967, Order of Culture
in 1968 and the First Class Order of the Rising Sun in 1974.

❷ Dr. MORIYAMA Yutaka
森山

豊 (1904 – 1988)
Dr. Morikawa was a gaynaecologist/obstetrician.
He intended to be a doctor when he was a high school student in Sapporo andgraduated Tokyo Imperial University in 1931. His great interest was prevending
congenital anomalies. The Japan Association for Maternal Welfare set forward
nation wide surveys on external malformations among the newborn and undertook
metabolic disorder screening under the presidency of Dr. Moriyama. He wasaward the Second Class Order of the Sacred Treasure ( 勲二等瑞宝章，right)
in 1977.

❸ KISHI Teruko
岸❹ Tachihikari Den’emon

輝子 (1905 – 1990)

太刀光電右衛門 (1897 – 1952)
Kishi was an actress. She

He was a sumo wrestler born

got a nurse after graduationas Hatta Masatsugu. He debutedof a high school, but started

in 1913 and promoted to ōzeki

at the lowest position of a(the second highest rank below

theatrical company to be

yokozuna in sumo) in 1923. It was aan actress. Her debut was

first promotion to ōzeki in wrestlers

in 1925. Her company was one of “shingeki”, which was afrom Hokkaido. Although he was

movement of modern theater in the twentieth century (shingeki

a relatively short but heavy sumomeans "new drama", against Japanese traditional one ofwrestler (170 cm in height, 113 kg in weight), he had good

Kabuki). She was famous as a good player of mother and old

throwing and foot techiques with a flexible body. He retired inwoman in many stages, movies and TV programs.

1927. His record is 67 wins – 26 losses – 6 draws – 2 holds –69 absents.
5

Introduction: Before you see the exhibition of humanities
As same as other regions of Hokkaido, at the latest, people settled in
Mikasa in Jōmon Period and then the culture of Ainu continued until Meiji.
In the early 19th century, Mikasa was developed as a coalmining town. At
that time, many prisoners contributed to that.
Before Modern History of Mikasa
In generally, humankind reached Japanese Archipelago in the glacial period, thirty thousands
years ago. Then, about ten thousands years ago, Jōmon Period（ 縄 文 時 代 ）characterizedby Jōmon (cord marked) potteries started. Although in Honshu (the mainland of Japan), Yayoi
Period（弥生時代）took over between the tenth to fourth century B.C. because agriculture
started, a similar culture to Jōmon, known as epi-Jōmon period（続縄文時代）continued in
Hokkaido. Satsumon culture（ 擦 文 文 化 ）followed epi-Jōmon period at about the seventh
century and then the culture of Ainu（アイヌ文化）displaced thatat the 13th century. Many place-names in Mikasa are derived from
Ainu language. For example, “Ikushumbetsu”, where the museum
locates, means “the far rever”.
On the other hand, people in Honshu called themselves “Wajin（和人）” to contrast to Ainu. The first Wajin came over to Mikasa waswoodmen in the 16th century.
Potteried and stone tools
In Mikasa, many potteries and stone tools are found in some archaeological sites. These
relics might be of Final Jōmon to epi-Jōmon period, but particular research is not carried out
until now.

Mikasa as a coalmine town
In 1868, just same time of Meiji Restruction ( 明治維新 , including Industrial Revolution ofJapan), the first coal was found from Mikasa. The Meiji government decided to development of
this area and Horonai Coal Mine（幌内炭鉱）started to operation in 1879. It was the firstmodern coal mine in Hokkaido.
Coal
Coal is a fossil fuel originates from ancient plants. In regard to Mikasa, origin of coal is woods 50 million years ago (theEocene to the Oligocene, the Paleogene).
First discovery of coal happened in 1868,and then many coalmines started tooperate. Numbers of miners assembled inthis town and created unique culture.
This locomotive is a 6 t storage
battery locomotive, 508 mm gauge(conversion from original 762 mm = 2 ft.
6 in.), manufactured in 1958, and used in
New-Horonai Coalmine due to safe riskof explosion.
6

Culture and Lifestyles of Miners
Coal mining by prisoners ended in 1897 and then private corporations
took over the mines. Horonai Mine ( 幌 内 炭 鉱 , operated in 1879 – 1989),
Ikushumbetsu Mine ( 幾春別炭鉱 , 1886 – 1957), and Pombetsu Mine ( 奔別炭鉱 ,1900 – 1971) were major mines in Mikasa. In addition, the Horonai Railway( 幌 内 鉄 道 ) was established in 1882 to bring coal from Mikasa to Otaru
Port. That was

❸ ❶
❺ ❹ ❷

the first railway
in Hokkaido,
and the third inJapan.
ENTRANCE❶ Tomoko

In Meiji Era, many skilled miners moved from Honshu to Hokkaido. Because these miners were belonging to guild-likeorganizations, called “Tomoko ( 友子 )”, same organizations spread to Hokkaido including Mikasa. Miners shared information
on mining technology and supported for each private lives such as wedding and funerals through this organizations. However
this organization supported miners’ business and lives in the late 19th to the early 20th century, this was phased out and finallydisappeared by the mid-20th century because changes of miners’ working conditions.
This scroll is a list new-coming miners. Masters' nameare written in larger letter and those of pupils are in smaller.
In Tomoko, relationships between a master and a pupil acted
as a parent and a child and helped each other.

See also → Guide Map of the tomoko graves
You can get it at the wicket
In this, it is described the outline and history of Tomoko and thelocations of Tomoko graves. You will learn more and more about
Tomoko system if you read this.

❷ Miner’s house
Miner’s house ( 炭鉱住宅 , Tanko-Jutaku, called 炭住 , Tanju for
short) was a terrace house for miners and their families. One Tanju
was divided into ten living unites and each unit was made by oneroom. This model is reconstructed one unit of a miner's house (butshortened its long).
Because the water and sewage systems weren't fitted up in houses,
there was no bathroom in each house. A lavatory room was set up as
an annex and a public bath was placed on each housing complex.
7After World War II, many coalmines in Japan tended to rationalize and mechanize toefficient mining. In Mikasa, the population of more than sixty thousands was largest in 1959
and the output was peaked in 1960s. But at the same time, major energy source changed fromcoal to oil. In addition, costs of coal mining became higher and therefore mines were closed
one by one in Mikasa.
❸ rack of headlamps
This rack combined with a battery charger ofheadlamps. A certain lamp was allocated to particularminer. Miners took out their own lamps from a rack
when they got down to a tunnel, and put back thosewhen they came back. In other words, this ruck was
utilized as an attendance book.
Coalmines were operated with three-shift 24-hourworking system. Small tags printed "1", "2", or "3"
indicate a shift of a owning miner, first shift (7 a.m. to
3 p. m.), second shift (3 p. m. to 11 p. m.), third shift (11p. m. to 7 a. m.) respectively.

❹ Mining Tools❺ Rescue in coalmines
This dummy wears equipments of a coalmine rescue. The
risk of accidents couldn't be fogetten in the operation of
coalmines. Of coalmines in Mikasa, some serious accidents
happened. In 1975, gas blew out and then was exploded in
Horonai Mine. 13 miners were killed in this accident. In 1971,
huge explosion was happend in Ponbetsu
Mine during closing operation ofmining tunnels. This killed 5
persons.
To add to transition of energy

Until 1950s, man-portable machines were main tools in coalsorce from coal to oil,mining in Japan. A coal mining team was composed by twothese risks of casualties

men. One was a sakiyama ( 先山 , means "front of mountain")drove management ofbreaks coal beds with man-portable machines, and anothercoalmines into thewas an atoyama ( 後山 , "rear of mountain") loads thosecrisis in Japan.

coals onto chain conveyors with shovels. 10 to 15 SakiyamaAtoyama teams were at work in a mining tunnel at once. At
that time, an output of coal was 2,000 t per day.
From 1960s downward, automation mining were tended to
introduced and an output increased to about 4,000 t per day. Ina single tunnel, about 150 persons engaged in digging.
In total, about 1,500 miners worked in a coal mine.

8

Exhibition about the Old-Prison
Establishment of a prison in 1882 is an epoch-making event in Mikasa.
This establishment was aimed isolation of prisoner from the mainland,
assembling of labors to development of Hokkaido, and settlement of
released ex-prisoners. In addition, because warden and their families
settled down❻near the prison,❸❷ ❶a town began.

❺❹

ENTRANCE❶ The prison
At that time, the prison in Mikasa ( 空 知 集
治 監 , Sorachi-shuchikan) was the largest one
in Hokkaido and held about three thousands
prisoners in peak. Almost all these prisoners weresentenced to more than 10 years imprisonment andwere forced to work at mainly building lords andmining of coal. Between 1883 to 1894, about 800– 1,200 prisoners per day worked in a mine.

❷ The Prisoners and the Warders
Some equipments of the prison are exhibited in this room.
The fetter is 20 kg in weight and was used when prisoners worked outside of theprison.
The sword was used by a guard. This sword is called "saber" in general but registeredas "wakizashi ( 脇 差 , a short katana used as a secondary)" with the police. In Meiji
Era, Japanese milirary and low enforcements changed there traditional equipments into
western ones andas a part of that,traditional katanas
were changed
its fittings into
western swords.

❸ The Warden (Governor) of the Prison
The first warden (governor) of the prison was Watanabe Koreaki ( 渡辺

惟精 , 1845–1900). He

concurrently holded the chief of the village, the chief of the police station, the director of the coalmine,and the director of the coalmine railway to administration of primitive this town. Many infrastructures
such as loads, waterworks, bridges, schools and hospitals were established under his management.
The chimney of his official residence is an only relic of the prison while other buildings werecompletely lost. In addition, his diaries held in this exhibition room show the dawn of this town.

9❹ Manufacture as penal labor
Furniture exhibited here is made byprisoners as penal industry. At the development
time, prisoners were expected as inexpensive
labor force. So prisoners pursued not only coalmining but also road laying, cultivation, housebuilding, woodwork, metalwork and so on.
As a result, the prison operated almost selfsufficiently.

❺ Waterworks
Water supply was an important problem toestablishment of a thousands-accommodations
prison in the wilds. There was no well andtherefore a waterworks were built from thesource 3 km away by prisoners in 1888. Thiswaterworks had filtration systems and cast-ironpipes. This was second modern waterworks
in Japan succeeded in Yokohama (1887) andpreceded in Hakodate (1889). This suppliedmuch water for not only the prison but also
the population in the town. The branch lines
for those were made by wood or bamboo andutilized after abolition of the prison (1901)
until 1940s.

❻ prisoners' grave
Freezing winter and hard prison industry took a heavy toll of prisoner’s lives. For 20
years when the prison existed, total number of the sick and wounded was more than 900
thousands and that of victims was 1,158.
For these victims, a cemetary was open in the northeast of the prison. But later, a site
for graves became short. Therefore a tombstone was established to bury all remains of
956 victims all together in 1896. After that, following victims were buried also under thistomb. Finally more than a thousand prisoners have slept in this tomb, and therefore iscalled “thousands persons’ grave ( 千人塚 , Sen’nin-Dsuka)”.
Today, the original tombstone is removed to this museum to prevent elosion, and therenewed one is installed in the cemetary.

10Animals, plants, and forestry gallery (The Annex)
Forests occupied 80 %of the area in Mikasa City
makes characteristics ofnature and culture in thiscity. The annex (ca. 100 m
east to the main building)displays specimens of local animals and plants lived in those forests.
Furthermore materials related to forestry are exhibited.
Caution! Closed from November to March.
❶ Brown bear

❷ Cabin of lumberjack
In Japan, Hokkaido isWhen lumberjacks

an only distribution ofworked in winter, they

higuma ( 羆， ヒ グ マ )made temporal cabins

or brown bear (Ursus

with pine, bamboo grass

arctus) , a same species as

and so on. This cabin isgrizzly (Alaska Peninsula

called “soma-goya ( 杣brown bear). It is the小屋 )” and reconstructedlargest terrestrial mammalin the annex.

in Japan.

Open-Air Museum
The Open-Air Museum is located on the south of the main building ofMikasa City Museum. It is a promenade in 1.2 km and you can see not only
coalmining remains and geological structures but also more than 350
plants along that.
See also → Open-Air Museum Area Guide Book (600 JPY)
This book explains 15 points of geological or coalmining historical view sights in the open-air museum area. It is also
introduced seasonal wild flowers you can see in this area.

<<< to Sapporo

Prefectural Road no. 116

to Furano >>>P
The main building

The annex(100 m east to the main buillding)

Ikushumbetsu River>>>

The open-air museum area(ca. 1.2 km in length)11