Conversations with Professor Prestwich #7
ICE ACTION

Dear Geoneophytes,

It is recorded that, on a visit to Blackford Hill in Edinburgh, Louis Agassiz pointed to some scratches on a smooth rock surface and opined that; “Ice has done this.” While Hutton and others had noticed evidence to suggest that the existing glaciers of Switzerland had once occupied a much greater area than they do today, this was the first time that anyone had suggested that ice had existed in a country with no glaciers. This observation initiated a profound change - a paradigm leap - in our understanding of the Earth’s recent history, as it led to an understanding of Ice Ages and a comprehension of large climatic shifts. Throughout Europe and North America, and eventually the rest of the globe, geologists delighted in recognizing the clues that “Ice has done this.”

Paradigm shifts increase the palette of possibilities and generally enrich our understanding of the world, causing all of us to re-consider our previous interpretations. Some results of this re-evaluation can embarrass, as Charles Darwin found out in the case of the parallel roads of Glen Roy.

Until the next time,

Joseph Prestwich