Corrie:

Physical Appearance:
- A corrie, also known as a cirque or a cwm, is a bowl-shaped hollow found on the side of a mountain.
- It is typically surrounded by steep, concave slopes on three sides, while the fourth side is open.
- The corrie has a rounded or semi-circular shape, resembling an amphitheater.
- It is often filled with a small lake or a glacier.

Mode of Formation:
- Corries are formed by glaciation, which is the process of glaciers eroding and shaping the land.
- The initial formation of a corrie begins when a glacier starts to move down a mountain slope.
- As the glacier flows, it erodes the underlying rock through processes such as plucking and abrasion.
- The erosive power of the glacier is concentrated in the area where the ice meets the bedrock, creating a hollow or basin.
- The hollow is often deepened by the process of freeze-thaw weathering, as water freezes and expands in cracks in the rock, causing it to break apart.
- As the glacier continues to move and erode the surrounding rock, the corrie becomes larger and deeper.
- Eventually, the glacier retreats due to changes in climate, leaving behind a bowl-shaped hollow.
- The hollow may be filled with water from melting ice and snow, forming a corrie lake.

Arete:

Physical Appearance:
- An arete is a narrow, sharp ridge that separates two glacial valleys or cirques.
- It is characterized by steep, rugged slopes on either side.
- Aretes can have a sharp, knife-like appearance.

Mode of Formation:
- Aretes are formed through the erosion of the ridge between two adjacent glaciers.
- As glaciers move down the slopes of a mountain, they erode the rock on either side of the ridge.
- The erosive power of the glaciers is concentrated along the divide, wearing it down over time.
- The process of plucking and abrasion carves out the ridge, creating a narrow, sharp edge.
- As the glaciers continue to erode the rock, the arete becomes more pronounced.
- The formation of an arete is often enhanced by freeze-thaw weathering, which breaks down the rock along the ridge.
- Aretes are commonly found in mountainous regions with glaciated valleys.

Erratic:

Physical Appearance:
- An erratic is a large, boulder-sized rock that is different in composition from the surrounding bedrock.
- Erratics can range in size from a few centimeters to several meters in diameter.
- They are often found in areas that have been glaciated.

Mode of Formation:
- Erratics are formed through the process of glaciation.
- When glaciers move, they pick up rocks and debris from the ground through plucking and abrasion.
- As the glacier advances, it carries the rocks with it.
- When the glacier eventually melts or retreats, it leaves behind the rocks in a different location.
- Erratics can be transported over long distances, sometimes hundreds of kilometers, by glaciers.
- The different composition of the erratic compared to the surrounding bedrock is often due to the rock being carried from a different source area.
- Erratics are commonly found in regions that have experienced glaciation, such