Agassiz Boulders

March 07, 2006

Agassiz_boulders copy

Provided and copyright by: Rob Sheridan
Summary authors & editors: Rob Sheridan

In the mid 19th century Louis Agassiz was arguably the world's most eminent natural scientist. Although originally trained as a physician, he was best known as a comparative zoologist and geologist. Most of his early glaciation work was done in his native Switzerland, where he lived atop a glacier for a time to facilitate his studies. He later moved to Cambridge, Massachusetts for a professorship (of both Zoology and Geology) at Harvard University.

At that time, it was generally assumed that the large boulders scattered about the New England landscape had been brought there by Noah's Flood. That ancient "ice ages" had altered the landscape was a difficult concept for even contemporary geologists to accept. To help convince a skeptical American geologic community of his glaciation theory, Agassiz used as an example a spectacular boulder field north of Cambridge, in Manchester-by-the-Sea, Massachusetts. These "erratics" were of granite resembling that found further north. The location and size of these massive boulders helped Agassiz convince a skeptical scientific community that the theory of ancient glaciation was plausible.

Agassiz died in 1873. The following year, the Manchester-by-the-Sea boulder field was named for him, and remains an obscure but pleasing destination for day-hikers. The two most spectacular erratics are called Little Agassiz and Big Aggasiz. In this photograph, taken on February 5th of 2006, a daring hiker stands atop an anonymous granite boulder adjacent to 'Little Agassiz' (directly behind). These erratics were probably deposited in their current location by the melting Laurentide Ice Sheet about 12,000 years ago.

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