Aletsch Glacier in Switzerland in 2010. Notice the horizontal trimline on the valley wall separating lush green from newly-exposed brown bedrock.
People who spend most of their time outside, such as farmers and mountaineers, have traditionally been the ones to notice changes in climate and the landscape around them before anyone else.
It was the observation of a mountaineer (Jean-Pierre Perraudin of the southern Swiss Alps) that connected the link between the marks and scars that he saw on bedrock at the glacier front to those he saw much further down the valleys.
He concluded that the glacier must have filled the valley at some point in the past, and he was prepared to share this idea with others (Jean de Charpentier). Scientists rejected this idea saying it was too extraordinary. It only took time and a few believers with open minds to get the ball rolling (or you might say “to get the erratic down the valley”).
There are many books and online resources that talk about ice age theory (I highly recommend reading Ice Ages: Solving the Mystery), but here I want to stress the point that you don’t have to be a trained scientist to make a profound observation. This mountaineer opened the minds of scientists, training them to imagine massive changes and to look for the evidence.
Sketches and paintings from the 1800s of Agassiz’s work on understanding glaciers are clear and stunning.
Jean de Charpentier organized and classified the evidence supporting the existence of large glaciers in the past and Louis Agassiz advocated for the theory of ice ages heavily, travelling to various locations in search for more evidence. The mind does not have to stretch too far to visualize glaciers in the European Alps growing down their valleys, but to fathom great ice sheets covering northern North America takes great skill and boundless imagination. While in Ellsworth, Maine, USA, Agassiz travelled with a ‘naturalist friend’, who might have been John K. DeLaski M.D.
Below is a geological conference abstract by: Borns, Harold W.
Title: JOHN K. DELASKI M.D. (1814–1874 ): PIONEER GLACIAL GEOLOGIST AND EARLY ADVOCATE FOR A CONTINENTAL ICE SHEET OVER NEW ENGLAND AND NEW BRUNSWICK
John K. DeLaski, M.D. practiced medicine in the Penobscot Bay region of Maine and, in addition, was a naturalist with keen powers of observation. His study of the landscape led to the conclusion that a thick glacier had overtopped the highest hills, flooded all of Penobscot Bay, extended far to the east and west and probably was part of a greater continental glacier. He published these very critical field observations and inferences in numerous articles in local newspapers and magazines, and in the American Journal of Science in 1864. His work put him on the “team” of Benjamin Silliman, James D. Dana and Louis Agassiz as an advocate for glaciation as the regional land shaping force opposed to that of the Biblical Deluge, a major scientific conflict of the day both in North America and Europe. He remained a shadowy player, in the background, but clearly contributed critical observations to the argument through personal interactions with Agassiz and other prominent naturalists. They incorporated DeLaski’s observations into their own presentations, often without giving him credit. John DeLaski’s summary work, a 400 page handwritten manuscript for the book, “The Ancient Great Glacier of North America”, was dated 1869. He died in 1874 and the book was not published. The manuscript currently resides with Professor H.W. Borns, Jr of the University of Maine.
I will remain in contact with Professor Borns about DeLaski and will post any updates on the manuscript.