# Timeline of geology

Timeline of geology

## 16th and 17th centuries

Portuguese and Spanish explorers systematically measure magnetic declination to estimate the geographical longitude [4][5]

## 18th century

• 1701 – Edmund Halley suggests using the salinity and evaporation of the Mediterranean to determine the age of the Earth
• 1743 – Dr Christopher Packe produces a geological map of south-east England
• 1746 – Jean-Étienne Guettard presents the first mineralogical map of France to the French Academy of Sciences.
• 1760 – John Michell suggests earthquakes are caused by one layer of rocks rubbing against another
• 1776 – James Keir suggests that some rocks, such as those at the Giant's Causeway, might have been formed by the crystallisation of molten lava
• 1779 – Comte de Buffon speculates that the Earth is older than the 6,000 years suggested by the Bible
• 1785 – James Hutton presents paper entitled Theory of the Earth – earth must be old
• 1799 – William Smith produces the first large scale geological map, of the area around Bath

## 19th century

• 1809 – William Maclure conducts the first geological survey of the eastern United States
• 1830 – Sir Charles Lyell publishes book, Principles of Geology, which describes the world as being several hundred million years old
• 1837 – Louis Agassiz begins his glaciation studies which eventually demonstrate that the Earth has had at least one ice age
• 1841 – August Breithaupt, Vollstandiges Handbuch der Mineralogie
• 1848 – James Dwight Dana, Manual of Mineralogy
• 1862 – Lord Kelvin attempts to find the age of the Earth by examining its cooling time and estimates that the Earth is between 20—400 million years old
• 1884 – Marcel Alexandre Bertrand, Nappe and Thrust fault theory