Who most influenced Darwin's idea that life could change slowly over a long period of time

Hutton and Lyell

Explanation:

James Hutton and Charles Lyell were geologists who believed the history of the Earth to be vast and directionless. James Hutton formed the theory of Uniformitarianism which was spread by Charles Lyell. According to this theory, Hutton and Lyell described that there are some forces present on the Earth which are involved in creating the vast history of the earth. They argued that Earth was far older than what other people believed and certain geological processes over a period of time shaped it.