Final answer:
Charles Lyell, a Scottish geologist, published the 'Principles of Geology', advocating for uniformitarianism, which posits that the same geological processes we observe today have always been at work. This principle, contrasting with catastrophism, extended Earth's age and had a profound impact on evolutionary theory, influencing thinkers like Charles Darwin.
Step-by-step explanation:
The Scottish geologist referred to in your question, who proposed uniformitarianism over catastrophism, is none other than Charles Lyell. In his seminal work, Principles of Geology, Lyell built upon the ideas of James Hutton, establishing the principle of uniformitarianism.
Uniformitarianism is the concept that the Earth's features developed from long-standing processes that still operate today, such as erosion and sedimentation. Lyell's work effectively argued against catastrophism, which was championed by Georges Cuvier and posited that Earth's geological landscape was shaped by sudden, short-lived, catastrophic events.
Charles Lyell's advocacy for a steady and continuous formation of Earth's geology implied a much older planet than previously thought, which consequently influenced the development of evolutionary theory by providing a timeframe sufficient for the gradual change in species, a concept that was a significant influence on Charles Darwin.