Drumlins are created as a result of ice being overloaded with material/debris – once the amount of debris exceeds the ice’s capacity to transport it, deposition occurs.
This may have been caused by the glacier reaching an obstacle, resulting in the loss of energy, and dropping the moraine, leaving it to build up are the obstacle. This deposition is streamlined and elongated by the advancement of ice flowing over it, creating the oval shape that resembles the side of an egg.
They can be a maximum of 1.5km long and 50-60m in height.
They are often found in groups known as ‘swarms’ and this is sometimes referred to as a ‘basket of eggs’.
They’re formed from unsorted till because the glacier loses its energy all at once, leading to the collective dropping of sediment.