Swiss-born zoologist, geologist and paleontologist Louis Agassiz (1807-73) was among the foremost scientists of his day. When he took up the study of glaciology and glacial geomorphology in Switzerland in 1836, he recorded evidence left by former glaciers, such as glacial erratics, drumlins and rock scouring and scratching. In this work, published in 1840, he proposed a revolutionary ice-age theory, according to which, glaciers are the remaining portions...