There is only one mention of loess in the 'Origin of Species':
"We have evidence in the loess of the Rhine of considerable changes of level in the land within a very recent geological period, and when the surface was peopled by existing land and fresh-water shells". (1859; Folio ed.p.305).
It is a very modest mention, but it merits some discussion. Some important geological concepts are embedded in this short quotation. We see Darwin indebted to Lyell for geological ideas. There are two Lyell concepts to the fore here- the importance of vertical movements of the land in geological processes, and the idea that loess is a lacustrine deposit. The lacustrine idea is used as an indicator, a verifier, for the vertical movement idea.
"We have evidence in the loess of the Rhine of considerable changes of level in the land within a very recent geological period, and when the surface was peopled by existing land and fresh-water shells". (1859; Folio ed.p.305).
It is a very modest mention, but it merits some discussion. Some important geological concepts are embedded in this short quotation. We see Darwin indebted to Lyell for geological ideas. There are two Lyell concepts to the fore here- the importance of vertical movements of the land in geological processes, and the idea that loess is a lacustrine deposit. The lacustrine idea is used as an indicator, a verifier, for the vertical movement idea.
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