The Great Devonian Controversy
Encyclopedia
The Great Devonian Controversy began in 1834 when Roderick Murchison
disagreed with Henry De La Beche
as to the dating of certain petrified plants found in coals in the Greywacke strata in North Devon
, England
. De La Beche was claiming that since Carboniferous
fossils were found deep in the Greywacke strata, which itself was older than Carboniferous
period, this method of dating rocks was not viable. Murchison, on the other hand, claimed that De La Beche did not place the fossils correctly, as they were occurring quite near the top of the strata as opposed to deep within it. De La Beche soon agreed with Murchison's argument as to the placing of fossils but maintained that since a layer of Old Red Sandstone, present in other formations, was missing between the layer of older rock and this new formation, there was still insufficient evidence to suggest the formation was not part of the older Silurian strata.
There followed much debate and some extensive investigations which ranged as far as Russia, where in 1840 Murchison discovered a layer similar to the one found in Devon placed between well defined Silurian and Carboniferous deposits. This discovery put an end to the Controversy and lead to a definition of a new period called Devonian
.
Roderick Murchison
Sir Roderick Impey Murchison, 1st Baronet KCB DCL FRS FRSE FLS PRGS PBA MRIA was a Scottish geologist who first described and investigated the Silurian system.-Early life and work:...
disagreed with Henry De La Beche
Henry De la Beche
Sir Henry Thomas De la Beche FRS was an English geologist and palaeontologist who helped pioneer early geological survey methods.-Biography:...
as to the dating of certain petrified plants found in coals in the Greywacke strata in North Devon
Devon
Devon is a large county in southwestern England. The county is sometimes referred to as Devonshire, although the term is rarely used inside the county itself as the county has never been officially "shired", it often indicates a traditional or historical context.The county shares borders with...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. De La Beche was claiming that since Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
fossils were found deep in the Greywacke strata, which itself was older than Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
period, this method of dating rocks was not viable. Murchison, on the other hand, claimed that De La Beche did not place the fossils correctly, as they were occurring quite near the top of the strata as opposed to deep within it. De La Beche soon agreed with Murchison's argument as to the placing of fossils but maintained that since a layer of Old Red Sandstone, present in other formations, was missing between the layer of older rock and this new formation, there was still insufficient evidence to suggest the formation was not part of the older Silurian strata.
There followed much debate and some extensive investigations which ranged as far as Russia, where in 1840 Murchison discovered a layer similar to the one found in Devon placed between well defined Silurian and Carboniferous deposits. This discovery put an end to the Controversy and lead to a definition of a new period called Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
.
Further reading
- Rudwick, Martin J. S. The Great Devonian Controversy: The Shaping of Scientific Knowledge among Gentlemanly Specialists. Chicago, University of Chicaco Press. 1985.