Because the mountains were a great distance from the sea, Darwin hypothesized that geological changes in the Earth brought them there over time.

Because the mountains were a great distance from the sea, Darwin hypothesized that major gradual geological changes in the Earth brought them there over time.

Explanation:

    Darwin's first discoveries were geological. He found sea shells on rocks 4,000 meters above sea level, which would help to prove the theory, which only emerged at that time, that the Earth had formed over millions of years. Today we accept this idea naturally, but at the beginning of the 19th century, it was a very radical thought.