The longest Devon sandstone outcrop in Estonia is located in Kallaste – the measurements done in 2001 showed that it is about 930 metres long. The maximum height of the outcrop is 8 metres. Starting from the south side of the town and moving towards the central square, you can see 11 outcrops. When water level rises during high waters, the waves chip away the outcrop, creating many caves in the sandstone. The largest of those are over 1.5 m high and up to 6 m deep.
The southernmost and highest outcrop is under nature conservation since 1959.