//Evolution sprang out of geology//
Do you have citations for this?
It's my own. At the time Darwin took his voyage, his only scientific training was in geology. By Darwin's time geology was dependent on fossils for identifying and sequencing strata. Geologists used fossils to determine relative ages of strata, but had no way of determining absolute ages.
One of the books Darwin took with him was Lyell's, which promoted uniformitarianism and implied a great age for geologic features. Thinking about gradual biological change was a parallel thought to thinking about gradual geological change.
Those are my words, but not my ideas. You can find them in any history of science.