The Origin of Species · Chapter
On the Poorness of Palaeontological Collections explained
Darwin argues that the geological record is extremely imperfect, citing the scarcity and fragmentary nature of fossils, the rarity of soft-bodied organisms, the dissolution of remains, and the vast intervals of time between formations.
What happens
Darwin argues that the geological record is extremely imperfect, citing the scarcity and fragmentary nature of fossils, the rarity of soft-bodied organisms, the dissolution of remains, and the vast intervals of time between formations. He explains that subsidence allows thick fossil-rich deposits to form, while elevation leads to destruction of strata, resulting in a biased and incomplete fossil record.
Themes in this chapter
Imperfection of the Geological Record
The chapter is entirely devoted to explaining why the fossil record is fragmentary, due to erosion, non-deposition, and the rarity of fossilization.
Extinction and the Succession of Forms
Discusses how subsidence leads to extinction and how formations rich in fossils are formed during such periods, linking to the succession of life forms.
Characters to notice
- Edward Forbes
Quoted as an admirable palaeontologist who noted that many fossil species are known from single or broken specimens.
- Sir Charles Lyell
Mentioned for discovering a land-shell in carboniferous strata and for his Manual's historical table on mammalian remains.
- Sir R. Murchison
Referenced for his great work on Russia showing wide gaps between superimposed formations.
Key passages
“The remark of that admirable palaeontologist, Edward Forbes, should never be forgotten, namely, that very many fossil species are known and named from single and often broken specimens, or from a few specimens collected on some one spot.”
Edward Forbes pointed out that many fossil species are based on just one or a few broken specimens from a single location.
Highlights the fragmentary nature of paleontological evidence.
“We can, I think, see why the geological formations of each region are almost invariably intermittent; that is, have not followed each other in close sequence.”
Geological formations in any region are usually not continuous but separated by gaps.
Explains the intermittent nature of the rock record.
“I am convinced that nearly all our ancient formations, which are throughout the greater part of their thickness rich in fossils , have thus been formed during subsidence.”
Most thick fossil-bearing formations were deposited while the land was slowly sinking.
Key conclusion linking subsidence to fossil preservation.