• During the Quaternary period Arran would have looked quite similar to what it looks like today. During the Quaternary period, Arran moved through a latitude of 55-55.5^oN, where it is today.  During this period the surface of the Island was acted on by numerous forces, in particular periods of Glacial Erosion. These multiple glaciation events eroded the surface of the island to look as it does today. For a detailed description of the events that took place in the quaternary, readers are referred to M^cKerrow and Atkins, 1989 and MacDonald and Herriot, 1983. During the Quaternary glacial activity, the northern Arran granitic mountains were thought to be a centre of ice sheet accumulation in their own right from that of the Scottish Highlands (Sissons, 1976).  The movement of the ice away from this centre eroded the mountains and gouged valleys to greater depths, thus producing classic U-shape valleys and hanging valleys, that can be seen in Glen Rosa (Image 1), and Glen Iorsa.

Image 1. The U-shaped valley of Glen Rosa, with hanging valleys on either side and to the rear.

• The granite mountains of Arran have two distinct types of peak, the peaks to the east of Glen Iorsa have jagged, rugged, angular high peaks, some examples being Cir Mhor and Goat Fell (Image 2). By contrast the western granite hills are more rounded, this is thought to have been related to more ice-sheet activity on the lower western mountains. At later periods in the glacial activity and the ice sheets were at lower heights, corries were developed on the northern sides of some of the peaks, i.e. the Devils punchbowl in Glen Sannox (Image 3.).

Image 2. Beinn a Chliabhain-Cir Mhor-Goat Fell

Image 3. A Qauternary corrie on the north eastern side of Cioch na h-Oighe, locally it is called the Devil's Punchbowl.

• There abundant depositional features on Arran related to the Quaternary glacial action. There is abundant boulder clay covering the southern part of  Island and some of the western part of the Island. Between Machrie and Dougarie, drumlin features have bee observed in the boulder clay.  In the glaciated valleys of the northern granite mountains, abundant moraines can be found. These terminal and lateral moraines were the last deposits of the retreating valley glaciers (Images 4 and 5).

Image 4. A glacial moraine deposit in Glen Rosa, the moraines are located on the floor of the U-shaped valley in a line of view with the tree in the foreground.