Great Ploughs

Glaciers are mechanical engines that grind, plough, and sculpt the earth. The 19th century natural historian Louis Agassiz wrote,

The glacier was God's great plough.
— Louis Agassiz, Geological Sketches, 1875.

Grey Glacier in the Southern Patagonian Ice Field, Chile

Glaciers leave a record of linear etchings, rubble, and deposited boulders from which we cobble the geologic narratives to reconcile what we see today.

The earth was covered by a huge ice sheet which buried the Siberian mammoths, and reached just as far south as did the phenomenon of erratic boulders. This ice sheet filled all the irregularities of the surface of Europe before the uplift of the Alps, the Baltic Sea, all the lakes of Northern Germany and Switzerland. It extended beyond the shorelines of the Mediterranean and of the Atlantic Ocean, and even covered completely North America and Asiatic Russia.
— Louis Agassiz, Études sur Les Glaciers, 1840, trans Albert V. Carozzi

Morteratsch glacier in the Bernina Range of the Bündner Alps, Switzerland

When the Alps were uplifted, the ice sheet was pushed upwards like the other rocks, and the debris, broken loose from all the cracks generated by the uplift, fell over its surface and, without becoming rounded, moved down the slope of the ice sheet.
— Louis Agassiz, Études sur Les Glaciers, 1840, trans Albert V. Carozzi

Mark Twain wrote of his experience visiting glaciers in The Alps. Twain wrote of feeling tolerably insignificant faced with the magnificence of The Alps, the new understanding of glaciers in the latter half of the 19th century that coincided with the burgeoning science of glaciology.

A man who keeps company with glaciers comes to feel tolerably insignificant by and by. The Alps and the glaciers together are able to take every bit of conceit out of a man and reduce his self-importance to zero if he will only remain within the influence of their sublime presence long enough to give it a fair and reasonable chance to do its work.
— Mark Twain, A Tramp Abroad, 1880.

REFERENCES

• A Tramp Abroad, Mark Twain, 1880.
• Études sur Les Glaciers, Louis Agassiz, Neuchatel, 1840.
• Geological Sketches, Louis Agassiz, Houghton, Mifflin and Company, 1875.