Complex sentence: The valley cuts through the Chiltern Hills in a north-west to south-east direction, the relatively narrow valley bottom is at 105m above sea level and rises up relatively steep sides to 180m to the plateau areas to the north and south.
Split into simpler sentences: The valley cuts through the Chiltern Hills in a north-west to south-east direction-the valley bottom is at 105m above sea level and rises up to 180m. It is a narrow, with relatively steep sides which rise up to the plateau areas to the north and south.