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Glossary I


Ice Age
Interval of geologic time between 2 million and 10,000 years ago during which the northern hemisphere experienced several episodes of continental glacial advance and retreat along with a climatic cooling. The icing over of Antarctica was also completed during this time.

Iceberg (see more about icebergs)
A large mass of floating ice that has broken off from a glacier, most of this is underwater.

Ice Dam
Also called (ice jam) occurs when water builds up behind a blockage of ice.

The fast-moving part of glaciers that have many crevasses. The ice in an average icefall moves at a speed of up to a few hundred meters each year (some move more quickly).

Ice Fishing
The act of fishing through holes cut in the ice. Usually from a shelter or hut.

Ice Sheet
A huge mass of glacial ice and snow that covers a large area of land; it is dome-shaped (for example, the Antarctic and Greenland ice sheets).

Ice Shelf
The part of an ice sheet that extends over the sea and floats in the water.

Ice Storm
Liquid rain falling and freezing on contact with cold objects creating ice build-ups of 1/4th inch or more that can cause severe damage.

Igloo (see more about igloos)
An effective, dome shaped shelter built from blocks of ice or compacted snow.

Igneous Rock
Rock formed when molten (melted) materials harden.

Imu (camping)
A shallow pit used for cooking.

Incoming Tide
Water pushing inshore, generally caused by the moon’s gravity pull. A strong wind blowing out to see can somewhat negate an incoming tide, however.

One of the three bones comprising the middle ear of mammals.

Indian Summer
An unseasonably warm period near the middle of autumn, usually following a substantial period of cool weather.

A small part of a body of water that reaches into a coast. A natural pass between ocean and bay.

In-Line Muzzleloader (hunting)
A hybrid rifle built to reflect the definition of a muzzleloading rifle according to many states’ game laws. In-line muzzleloaders are in many respects modern rifles using primitive technology. The rifles are loaded with black powder or Pyrodex via the muzzle and using a ramrod, but the powder is often pelletized and shooters often use saboted copper-jacketed bullets that would not otherwise be capable of loading in a muzzleloader. As well, the rifles use a modern “in-line” ignition system with a bolt that is similar to a high-powered rifle. The performance of an in-line muzzleloader is something between a primitive muzzleloader and a high-powered rifle.

An animal with three main body parts and six legs.

An animal which feeds on insects.

Prominent steep-sided residual hills and mountains rising abruptly from plains. The residuals are generally bare and rocky, large and small, isolated and in hill and mountain groups, and they are surrounded by lowland surfaces of erosion that are generally true plains, as distinguished from peneplains.

Inside Spread (hunting)
The distance between an animal’s antlers measured at the widest point on the inside of each antler. This distance can be radically different than the outside spread, depending on whether or not the antlers have non-typical points on the outside.

Iron Sights (hunting)
A pair of sights set atop the barrel of a rifle, one on the end of the barrel and the other near the breech of a rifle for accurate shot placement. Iron sights are very traditional and low-tech, and do not magnify the shooter’s vision.

Island (see more about Islands)
A piece of land that is surrounded by water.

A line on a map connecting points that receive equal precipitation.

Isothermal Layer
A layer of the ocean or atmosphere in which the temperature is constant.

Isthmus (see more about an Isthmus)
A narrow strip of land connecting two larger landmasses. An isthmus has water on two sides.