Not only did he collect widespread evidence of the uplift of the coast during the earthquake, but traveling inland and into the mountains, he discovered a series of remains of marine shells — proof that the shifting that had recently uplifted the coast by a small amount had occurred over and over in the recent geological past.

The experience convinced him that the great geologist Charles Lyell was right — mountain chains were not created by sudden immense catastrophes, but grew almost imperceptibly, the product of thousands of successive uplifts over almost endless geological time.