Notes on Library of Congress Subject Headings (LCSH) chronological subdivisions

1: Examples of chronological subdivisions (6XX$y)

Chronological subdivisions ($y)

1 Roman period, 55 B.C.-499 A.D.

2 Wars of the Roses, 1455-1485

3 Middle ages, 600-1500

4 Cultural Revolution, 1966-1976

5 1918-1945

6 1929

2: Examples of chronological subdivisions under the subject heading: United State-History

Chronological subdivision

1 Colonial period, ca. 1600-1775

2 Revolution, 1775-1783

3 Civil War, 1861-1865

4 Confederation, 1783-1789

5 War with Mexico, 1845-1848

6 World War, 1914-1918

3: Geographic headings with "Civil war" as chronological subdivision

Geographic heading Chronological subdivision

Great Britain Civil war, 1642-1649

United States Civil war, 1861-1865

Spain Civil war, 1936-1939

China Civil war, 1945-1949

Nigeria Civil war, 1967-1970

Map visualization for "Civil wars"

This display could be used both to provide a geographical visualization of retrieval results and as an interface allowing one to click on a particular civil war to search for materials about it.

4: Examples of actual LCSH in marked-up MARC format

LCSH

1 <650><a>Secret service</a><z>United States</z><y>Civil war, 1861-1865.</y></650>

2 <651><a>Cambodia</a><x>History</x><y>Civil war, 1970-1975</y><x>Personal narratives, American.</x></651>

3 <650><a>United States</a><x>Economic conditions</x><y>1865-1918.</y></650>

4 <651><a>Scotland</a><x>Intellectual life</x><y>20th century.</y></651>

5 <650><a>Freedom of speech</a><z>United States</z><x>History</x><y>20th century.</y></650>

6 <651><a>California</a><x>History</x><y>1846-1850.</y></651>

	Chronological subdivisions ($y)
1	Roman period, 55 B.C.-499 A.D.
2	Wars of the Roses, 1455-1485
3	Middle ages, 600-1500
4	Cultural Revolution, 1966-1976
5	1918-1945
6	1929

	Chronological subdivision
1	Colonial period, ca. 1600-1775
2	Revolution, 1775-1783
3	Civil War, 1861-1865
4	Confederation, 1783-1789
5	War with Mexico, 1845-1848
6	World War, 1914-1918

Geographic heading	Chronological subdivision
Great Britain	Civil war, 1642-1649
United States	Civil war, 1861-1865
Spain	Civil war, 1936-1939
China	Civil war, 1945-1949
Nigeria	Civil war, 1967-1970

	LCSH
1	<650><a>Secret service</a><z>United States</z><y>Civil war, 1861-1865.</y></650>
2	<651><a>Cambodia</a><x>History</x><y>Civil war, 1970-1975</y><x>Personal narratives, American.</x></651>
3	<650><a>United States</a><x>Economic conditions</x><y>1865-1918.</y></650>
4	<651><a>Scotland</a><x>Intellectual life</x><y>20th century.</y></651>
5	<650><a>Freedom of speech</a><z>United States</z><x>History</x><y>20th century.</y></650>
6	<651><a>California</a><x>History</x><y>1846-1850.</y></651>