Agassiz Rock is a park in Manchester-by-the-Sea, Massachusetts

Manchester-by-the-Sea, Massachusetts

Manchester-by-the-Sea is a town on Cape Ann, in Essex County, Massachusetts, in the United States. As of the 2000 census, the town population was 5,228.-History:...

 that is owned and maintained by The Trustees of Reservations

The Trustees of Reservations

The Trustees of Reservations is a non-profit land conservation and historic preservation organization dedicated to preserving natural and historical places in the Commonwealth of Massachusetts. It is the oldest regional land trust in the world and has 100,000 dues-paying members...

. It takes its name from two dramatic examples of large boulder

Boulder

In geology, a boulder is a rock with grain size of usually no less than 256 mm diameter. While a boulder may be small enough to move or roll manually, others are extremely massive....

s plucked from bedrock

Bedrock

In stratigraphy, bedrock is the native consolidated rock underlying the surface of a terrestrial planet, usually the Earth. Above the bedrock is usually an area of broken and weathered unconsolidated rock in the basal subsoil...

 and carried by the glacier

Glacier

A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...

s.

As the glaciers scoured this landscape, the mass of bedrock forming the hill proved more resistant than the surrounding soil, forcing the bottom of the glacier up and over the hill. The north side was smoothed and the south side left steep and rugged as the glacier broke off chunks of rock

Rock (geology)

In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...

 as it passed.

A short loop trail leads up Beaverdam Hill where Little Agassiz Rock appears as a giant granite

Granite

Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...

 monolith

Monolith

A monolith is a geological feature such as a mountain, consisting of a single massive stone or rock, or a single piece of rock placed as, or within, a monument...

 silhouetted against the sky. It rests precariously on a small jagged stone

Rock (geology)

In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...

, leaving an opening below.

A short distance away, other boulders lie perched on the edge of this glaciated upland. Below, in a small shrub

Shrub

A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

 swamp

Swamp

A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...

, rests thirty-foot-tall Big Agassiz Rock. How far it extends underground is unknown.

The is a one mile moderately difficulty loop trail that passes both Big and Little Agassiz Rocks. Following long periods of rain

Rain

Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...

 the immediate area surrounding Big Agassiz Rock often floods.

History

In 1874, a group of students named this site to honor Louis Agassiz

Louis Agassiz

Jean Louis Rodolphe Agassiz was a Swiss paleontologist, glaciologist, geologist and a prominent innovator in the study of the Earth's natural history. He grew up in Switzerland and became a professor of natural history at University of Neuchâtel...

, the Harvard University

Harvard University

Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...

 professor who first theorized that the rocks that dot New England

New England

New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...

's landscape were shaped and deposited by glaciers.

Agassiz visited the site and found its erratic physical features fit his theory. Prior to Agassiz's theory, it was widely believed that the scattering of rocks throughout New England were the result of Noah

Noah

Noah was, according to the Hebrew Bible, the tenth and last of the antediluvian Patriarchs. The biblical story of Noah is contained in chapters 6–9 of the book of Genesis, where he saves his family and representatives of all animals from the flood by constructing an ark...

's flood.
the rock is often used as a type example of a Glacial Erratic.